JP3476864B2 - Glass manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing glass via a porous body.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a multi-component glass via a porous body, firstly, hydrolysis of a metal alkoxide or the like, polycondensation reaction, water glass or oxide particles such as SiO ₂ is used. A sol-gel method using a porous gel prepared by adjusting the pH of a sol in which is dispersed in a solvent. Second, alkali-borosilicate glass is melted, phase-separated by heat treatment, and a soluble phase is formed by acid treatment. A method of utilizing a porous body produced by elution (Japanese Patent Publication No. 61-21173), and thirdly, a porous body produced by depositing metal oxide particles as represented by the CVD method. A method (ceramics, 21 (1986) 419-424) and the like have been proposed.

FIG. 1 shows an outline of a process for producing a multi-component glass via a porous body. A porous material containing metal ions is fixed in a state where there is no concentration distribution in the metal ions (Fig. 1
A homogeneous glass can be produced by fixing 1) and drying and firing in the steps (1), (2) and (5). On the other hand, if the metal ion is given a concentration distribution and then fixed (fixed 2 in FIG. 1), and dried and baked in the steps (1) to (5), a glass having a refractive index distribution and the like is produced. You can

Conventionally, various methods have been proposed for fixing a metal component in a porous body depending on the strength and properties of the porous body. When using phase-separated glass, first, the pores are impregnated with a nitrate aqueous solution of a dopant at about 100 ° C.,
Fill the pores with metal nitrate (stuffing process). Next, the solution containing the metal nitrate ion of the dopant impregnated in the pores is gradually eluted out of the porous glass by immersing it in a solution capable of diffusing the metal nitrate (ethanol-water mixed solution at about 70 ° C.) ( Unstuffing process), giving concentration distribution. Then, in order to fix this concentration distribution, it is immersed in ethanol having a low solubility near 0 ° C. to precipitate fine crystals, which is then dried and heat-treated to produce a dense glass. Such a method of producing a glass having a refractive index by the so-called molecular stuffing method is disclosed in Japanese Patent Publication No. 61-21173.

A sol-gel method is used to prepare a porous gel by adding a solution containing an alkoxide of Si as a main component and a water-soluble salt of a specific metal ion, and drying and firing the porous body. In the method for producing glass, a method of producing a multi-component glass in which a metal component is introduced by immersing a porous body in an organic solvent which has low solubility in the salt and is mixed with water is disclosed in JP-A-63-277525. It is disclosed in the publication. Further, Japanese Patent Publication No. 2-24773 discloses a method for producing a multi-component gel by using a metal alkoxide by the sol-gel method. in this case,
Generally, a metal salt and a metal alkoxide are used as raw materials. In order to obtain a homogeneous gel by using these raw materials by the sol-gel method, it is desired to use these in a state of being dissolved in a liquid. However, among the metal alkoxides, those having high solubility in water and alcohol are limited to alkoxides such as Si, Ti, Ge, Zr, Al, P and B. Therefore, when it is desired to introduce a metal component having a low solubility of the metal alkoxide, a method of using a metal salt having a high solubility is an effective method in that the variation of the metal composition is greatly expanded.

As a method for producing a glass having a refractive index distribution by using a metal salt by the sol-gel method, there is disclosed in JP-A-3-
There is a method described in Japanese Patent No. 295818. In this method, a sol is prepared from a silicon alkoxide and a salt of lead, which is a metal for imparting a refractive index distribution, then gelled, and the gel is immersed in a solution to obtain the concentration of the salt in the gel. It is a method of giving a distribution to obtain a glass having a refractive index distribution. The steps include (1) introducing a metal salt into the sol and gel, (2) fixing the introduced metal salt in the gel, and (3) eluting the metal salt fixed in the gel to form a metal salt. A step of imparting a concentration distribution, (4) a step of fixing again in the gel so that the concentration distribution imparted in (3) above is not disturbed, (5) a solvent in the gel is dried and sintered to obtain a glass. The process consists of obtaining. Here, the steps (2) and (4) are the same in principle, and the wet gel is sequentially immersed in a solution having a low solubility of the lead salt to form fine crystals of the lead salt. This is a method of precipitating in the pores to fix the lead distribution.

Using this method, the above steps (1) to
As described above, the glass having the composition distribution can be obtained by performing the step (5), and the homogeneous glass can be produced by performing the steps (1), (2) and (5) in this order. .

Further, the behavior of the metal salt in the gel by this method will be described in detail. When a wet gel is prepared by introducing a metal species other than silicon as a metal salt (for example, lead acetate) into a silica sol produced by the sol-gel method, the metal salt exists in the porous gel in a state of being dissolved in a solvent. By dipping this gel in a mixed solvent of isopropanol and acetone at a gradually increasing mixing ratio of isopropanol and acetone, the lead acetate microcrystals were deposited on the walls of the pores in the gel. , Fixed. Here, the solubility of lead acetate is smaller in acetone than in isopropanol, and in a mixed solvent system, the solubility becomes smaller as the proportion of acetone increases, so that lead acetate precipitates.

Next, in the distribution imparting step, the gel is dipped in a distribution imparting liquid to impart a metal concentration distribution to the gel. Ethanol is used as the distribution-imparting liquid used here. Since the solubility of lead acetate in ethanol is relatively high, the infiltration of ethanol into the gel causes the lead acetate microcrystals that have once precipitated and fixed on the gel pore walls to dissolve and
Is eluted. The distribution shape of lead acetate can be controlled by controlling the immersion time in the distribution-imparting liquid. By sequentially immersing the gel in a mixed solvent of isopropanol and acetone again, the crystals once dissolved at the time of imparting the distribution are precipitated again as fine crystals and fixed in the gel. By drying this gel and firing the obtained dry gel, glass having a refractive index distribution in the radial direction can be obtained.

The system using the metal salt and solvent used therein has been described above based on the examples in the above publications, but this principle can be applied to many other metal salts. Expected to be.

[0011]

Problems to be Solved by the Invention JP-A-63-2775
According to the method using a water-soluble metal salt disclosed in Japanese Patent Laid-Open No. 25, for example, compounds (salts) such as acetates, nitrates and chlorides are used. However, in order to fix such a metal component in the porous gel, when the porous gel is immersed in an organic solvent having low solubility in the salt and mixed with water, a part of the metal salt in the porous gel is As described above, microcrystals are deposited and fixed in the porous gel pores, but the rest is dissolved in the solvent in the porous gel pores and is eluted out of the porous gel to form crystals. It precipitates in the organic solvent.
On the other hand, in order to suppress crystal precipitation in this organic solvent,
Conversely, when the solvent type or mixing ratio is changed to one with a high solubility in the metal salt, the metal salt is dissolved in the solvent and elutes out of the porous gel, so it is fixed in the porous gel. The amount of metal salt remaining was only small.

[0012] Depending on the metal element to be introduced, there is also a metal compound such as a rare earth element in which acetate has a low solubility in water or alcohol. For example, when an acetate salt or the like is used, the solubility cannot be sufficiently ensured, so that it cannot be contained in a large amount in the porous body, or in the method of previously adding the metal ion to the sol by using the sol-gel method, The solvent had to be used, which ended up diluting the sol. For this reason, the strength of the gel is lowered and cracks occur very often, and it has been difficult to produce glass having a desired shape.

In such a case, a salt such as nitrate or chloride is used instead of acetate. In this case, JP-A-6
In JP-A-3-277525, a porous body is immersed in an organic solvent miscible with water to precipitate and fix fine crystals, but chlorides and nitrates have high solubility in such organic solvents, Since it was dissolved in the immersion solvent, it was difficult to completely fix it in the porous body.

That is, for metal species such as rare earth elements, in which the use of metal salts such as nitrates and chlorides is unavoidable, the degree of crystal precipitation varies depending on the type of immersion solvent, but any solvent is used. It was difficult in this conventional method to immobilize the gel while leaving the metal salt in the gel.

Next, problems in manufacturing a gradient index optical element according to Japanese Patent Laid-Open No. 3-295818 will be described. An essential step in this manufacturing method is a step of imparting a concentration distribution to the metal salt in the porous gel, but as described above, in the distribution imparting step, one of lead acetate is contained in the porous gel pores. Part is in the state of fine crystals, and the rest is present in a state of being dissolved in the distribution-providing liquid solvent. Distribution distribution is controlled by permeation of the distribution distribution liquid and dissolution and diffusion of lead acetate. At this stage, the distribution shape of lead acetate does not have an inflection point in the radial direction, as shown in FIG. It is considered that the shape is monotonically increasing.

When such a wet gel is immersed in a solution having a low metal salt solubility, the solution in the pores gradually becomes less soluble in the metal salt as the solution permeates, and the metal salt is slightly dissolved. Precipitates as crystals. At this time, the pore size distribution of the wet gel is about 10 to several hundred angstroms, and the speed of movement of the solution in the pores is small. Therefore, the exchange of the solution in the pores with the solution outside the gel proceeds slowly. During this period, the metal salt dissolved in the solution in the pores was apt to move toward the outer periphery of the gel, and the concentration distribution of the metal added in the distribution giving step collapsed, or the concentration distribution was given. In the step of fixing lead acetate, the fixing was not sufficient, and in the step of drying the wet porous gel, lead acetate slightly dissolved in the solution for fixing was transferred to the outer peripheral part due to the movement of the solvent during the drying. It was observed that the particles moved and had a concentration distribution with an inflection point on the outer peripheral portion as shown in FIG. The refractive index distribution of the glass thus obtained has an inflection point in the radial direction, and has limited applications and a narrow application range due to optical design.

In addition, since crystals are gradually precipitated in the porous gel at the time of fixation after the distribution is imparted, the solvent exchange step becomes multi-step, so that a large amount of solvent is required as the immersion liquid, and the whole step. Has become a long time. Thus, immersing for a long period of time caused the inconvenience that the concentration distribution of the metal salt added in the distribution giving step was likely to collapse. In order to avoid these problems, we attempted measures such as changing the solvent mixing ratio to reduce the solubility, but elution outside the porous gel was unavoidable, and crystal precipitation was observed in the fixative due to the decrease in solubility. However, the collapse of the concentration distribution was not improved.

The relationship between the amount of the metal salt fixed in the pores of the porous gel and the amount eluted out of the gel differs depending on the kind and amount of the metal salt, and the ratio should be compared unconditionally. I can't. However, in any case, there is a limit to the method disclosed in Japanese Patent Laid-Open No. 3-295818 by changing the mixing ratio of the solvent and precipitating the metal salt microcrystals due to the difference in solubility, depending on the metal species to be introduced, or Experimental results have shown that a sufficient effect cannot be obtained depending on the required fixing accuracy (for example, reliable holding of the distribution shape when manufacturing a gradient index optical element).

Further, also in the case of producing a glass having a refractive index distribution by the so-called molecular stuffing method, there are the same problems as described above. In order to contain a large amount of metal components, it uses a highly soluble nitrate, and the distribution is fixed by a temperature difference of about 100 ° C and a solvent with a low solubility, but nitrate is generally a polar solvent such as water or alcohol. It has a high solubility in, and even in ethanol near 0 ° C, it still has a solubility of about 1g / 100ml as a nitrate, and it is difficult to completely fix the metal in the porous body, and it dissolves in the fixing solution. Since the metal salt which is moved moves during the drying process, it is not possible to give a concentration distribution with sufficient accuracy, and it is difficult to give a large difference in refractive index.

All of these are problems that occur when the metal salt is fixed in the porous body, and the present invention provides a method of introducing a metal species into the porous body by using the metal salt. An object of the present invention is to provide a method capable of reliably fixing a metal salt existing in a dissolved state in body pores in the pores of a porous body.

[0021]

[Means for Solving the Problems] To solve the above problems
The method for producing glass according to the present invention includes (1) metal alkoxide
Via a wet gel, which is a porous body made with sid
When manufacturing multi-component glass,
In the process of fixing the gel in a wet gel, an organic acid or an organic acid
Solution containing at least one compound selected from salts
Contains the metal salt dissolved in the solvent in the pores
Immerse the wet gel in the solution, and set the metal salt to
Crystallized in pores and fixed in wet gel
And In addition, (2) was prepared using a metal alkoxide
Multi-component glass via wet gel, which is a porous body
In manufacturing, the metal component is fixed in the wet gel.
In the process, a compound selected from organic acid or organic acid salt.
A solution containing at least one substance in the pores
Wet gel containing metal salt dissolved in solvent Soaking
Then, the metal salt as fine crystals of an organic metal salt in the pores.
Then the wet gel has a low solubility of the metal components.
And dip it in a solvent that is miscible with water.
It was decided to fix the crystals in a multi-wetting gel. Also,
(3) A porous body prepared by using a metal alkoxide
Manufacturing glass with refractive index distribution via wet gel
In doing so, after giving the metal component a concentration distribution,
In the process of fixing the concentration distribution, dissolution of the metal components
A solvent that is less soluble and miscible with water may have an organic acid or
Contains at least one compound selected from organic acid salts
The solution is provided with the above concentration distribution and metal
Wet gel containing salt dissolved in the solvent in the pores
Immerse the metal salt in the pores as organic metal salt microcrystals
It was made to precipitate in and fixed in a wet gel. Also,
(4) A porous body produced using a metal alkoxide
Manufacturing glass with refractive index distribution via wet gel
In doing so, after giving the metal component a concentration distribution,
Dissolution of the metal components in the process of fixing the concentration distribution
A solvent that is less soluble and miscible with water may have an organic acid or
Contains at least one compound selected from organic acid salts
The solution is provided with the above concentration distribution and metal
Wet gel containing salt dissolved in the solvent in the pores
Immerse the metal salt in the pores as organic metal salt microcrystals
The wet gel, and then the solubility of the metal component is increased.
Dip in a solvent that is low and miscible with water to obtain the above concentration distribution.
Immobilization of microcrystals of a given organometallic salt in a wet gel
And In the case of (1) to (4), the organic acid or
Contains at least one compound selected from organic acid salts
By changing the concentration of the solution over time,
High effect can be obtained. In the above (1) to (4),
As a compound selected from the organic acids or organic acid salts,
Acetic acid, citric acid, malic acid, maleic acid, oxalic acid, milk
At least a compound selected from acids and salts thereof.
A higher effect can be obtained by using a solution containing one type
can get.

[0022]

[Function] Wet, which is a porous material produced by the sol-gel method
Incorporate a metal salt into the gel so that the metal salt dissolves in the pores.
Dissolve in the medium. Dissolve the wet gel body in this state
Immerse it in a low-grade solvent, but use an organic acid or organic acid salt.
At least 1 selected from When immersed in a solution containing
As shown below, simply soaked in a solvent with low solubility
Compared with the case, more crystallites can be precipitated.
it can.

In the fixed solvent alcohol, the organic acid H
_a X dissociates as shown in Chemical formula 1.

[0024]

[Chemical 1]

Further, the equilibrium of Chemical formula 2 is established between the organic acid ion and the metal ion.

[0026]

[Chemical 2]

Here, Me is a metal element and X is an organic acid ion. Of 1 from X ^a- is to be supplied by the organic acid or organic acid salt, balance of 2 is moved to the left, a precipitate formed. At this time, considering the solubility product, it becomes as shown in Chemical formula 3.

[0028]

[Chemical 3]

The combination of the metal ion, the organic acid and the organic acid salt that can be used at this time has a sufficiently small solubility product shown in Chemical formula 3, and more metal components than the conventional method can be used. Can be fixed sufficiently. As the organic acid and the organic acid salt, for example, acetic acid, citric acid, malic acid, maleic acid, oxalic acid, lactic acid or the like and salts thereof can be used, or a mixture thereof may be used.
The porous body may be dipped in the solution multiple times.

These organic acids or organic acid salts are selected in consideration of the decomposition temperature, the acid dissociation constant, the addition amount of these, and the like. Therefore, the crystal precipitation rate can be controlled by the type and amount of the organic acid or the like added.

Particularly, rare earth elements, which have been difficult to be introduced in large amounts in the past, are chlorides or nitrates, or when salts having low solubility in water or alcohol are used, for example, acetates and acetylacetones are used. salt,
A gel prepared by dissolving a metal alkoxide in hydrochloric acid to increase its solubility is immersed in a solution containing an organic acid or an organic acid salt to produce organic metal salt microcrystals by the reaction of the organic acid ion and the metal ion. To deposit. Therefore, many fine crystals can be precipitated in the gel. In this way, it is possible to uniformly dope a large amount of metal into a glass, which cannot be doped into the glass in a large amount due to crystal precipitation or low solubility.

Further, also when producing glass having a refractive index distribution, fixing treatment can be carried out by causing an organic acid to act on the same principle. Fixing process after the distribution process (Fig. 1
In the fixing step 2) in the inside, the rapid fixing can significantly reduce the above-mentioned collapse of the distribution. Therefore, even during the subsequent drying step, the metal salt in the porous body is firmly fixed and does not move in the porous body to destroy the distribution shape, and the metal concentration distribution shape is formed. It is possible to produce a porous body having sufficient accuracy. Then, by subsequently calcining this porous body, the fine crystals of the metal salt precipitated in the pores are easily decomposed and taken into the porous body, and the target glass can be produced by making it non-porous. it can.

The organic acid or the organic acid salt works effectively not only when it is added to the distribution fixing solution from the beginning, but also when it is added during the immersion. Because, depending on the selection method of the metal salt, the solvent, the organic acid, etc., when the organic acid or the organic acid salt is added at one time, the crystal precipitation action may be too strong and the porous body may be damaged. . In such a case, a high effect can be obtained by fixing the organic acid or the organic acid ion in the solution by changing the concentration thereof with time.

As a method, for example, an organic acid or an organic acid salt is dropped, and the concentration of the organic acid or the organic acid salt added here varies depending on the kind of the organic acid or the organic acid salt to be added. It may be determined in consideration of the dissociation constant and the like. As a result, the number of steps for solvent exchange can be reduced, and the time required for the entire process can be reduced. Furthermore, in particular, when producing glass in which the characteristics such as the refractive index are distributed, the concentration of the organic acid or the organic acid salt in the solution containing the organic acid or the organic acid salt is several hundreds of normal to several minutes. Even with one regulation, it has an effect and the metal salt is fixed as fine crystals in the porous body sufficiently, so the amount of solvent can be significantly reduced compared to the conventional method using a large amount of solvent. Becomes

The porous body containing the metal element may be prepared by any method, and after preparing a sol by previously dissolving a salt of a rare earth element or the like in water by the sol-gel method. The porous body gel may be produced by gelling, or the porous body gel may be produced by immersing the porous body gel in a solution of a metal element. Further, the gel thus produced may be dried or fired to produce a porous body. Further, the porous body used may be a porous body produced by a CVD method or a porous body produced by phase-separating glass.

[0036]

Example 1 15.5 ml of Si (OC ₂ H ₅ ) ₄ and 4
Mix 3.1 ml 1-propanol, then 1.25
After adding 1 ml of 1/100 N HCl aqueous solution and stirring for 60 minutes to partially hydrolyze the mixture, 9.0 g of Al (Os) was added.
was stirred _{ec-C 4 H 9) 2} (C 6 H 8 O 3) was added for 60 minutes. Next, 10.2 g of La (CH ₃ COO)
₃ of 16.3ml was dissolved · 1.5H ₂ O 3N-HC
After adding 1 and stirring, it was poured into a polypropylene beaker and gelled to obtain a wet gel. The wet gel was aged at 60 ° C. for 7 days, and successively dipped in a 4N acetic acid aqueous solution and ethanol. The gel is dried at 100 ° C and 140
When fired to 0 ° C, 70SiO ₂ · 15Al ₂ O
_{3 · 15La 2 O 3 (mol} %) Glass homogeneous target composition without striae and impurities composition was obtained.

Comparative Example 1 A sol was prepared in the same manner as in Example 1 to obtain a gel. Soak this gel in ethanol and dry at 100 ° C to
When fired up to 400 ℃, 78SiO ₂ · 15Al
_{2 O 3 · 7La 2 O 3} (mol%) becomes the composition, it was not possible to obtain a glass of the target composition.

[0038]

Example 2 To 88.1 ml of Si (OCH ₃ ) ₄
51.8 ml isopropanol, 10.7 ml 1 /
After adding 100 N HCl aqueous solution and stirring for 30 minutes to partially hydrolyze, 42.64 g of Ti (OiC
₃ H ₇ ) ₄ was added and stirred for another 30 minutes. next,
15.3 g of silica powder (Aerosil (Aerosi
(Company 1)) was mixed with a solution dispersed in 108.0 ml of isopropanol. After that, 26.8 g of Y (OCH
₃ ) 200 ml of a hydrochloric acid aqueous solution in which ₃ was dissolved was added dropwise, and the mixture was stirred and hydrolyzed to prepare a sol. This sol was placed in a polypropylene container, sealed, and gelled to obtain a wet gel. The wet gel was immersed in a 0.2 mol / l citric acid aqueous solution for 12 hours, and then immersed in a mixed solution of isopropanol and acetone for 24 hours. When this gel was dried at 60 ° C and the temperature was raised to 1400 ° C, no striae were observed and a homogeneous and transparent 74SiO ₂ · 13TiO ₂ · 1.
Glass having the composition of 3Y ₂ O ₃ (mol%) was obtained.

[0039]

Example 3 4.81 ml of Si (OCH ₃ ) ₄ and 1
Mix 1.4 ml ethanol, then 0.6 ml 1
/ 100N HCl aqueous solution was added, the mixture was stirred for 60 minutes, and after partially hydrolyzing, 4.5 g of Al (Osec-C ₄
H ₉₎ was stirred _{2 (C 6 H 8 O 3} ) was added for 60 minutes. Next, 2.5 g of Ti (OiC ₃ H ₇ ) ₄ was added and stirred for another 30 minutes. There, 8.7g of La (N
O _{3) 3} · 6H ₂ O was dissolved 25.0ml of 1N-H
After adding Cl and stirring, the mixture was poured into a polypropylene beaker and gelled to obtain a wet gel. The wet gel was aged at 60 ° C. for 3 days to give 0.3 mol / l EDT.
It was immersed in A and La was fixed. Next, methanol: H ₂
It was immersed in a solution of O = 6: 4 (volume ratio) to give La a concentration distribution. Then, the gel was successively dipped in ethanol and acetone, and the gel was dried at 100 ° C. and baked to 1380 ° C., and glass having a refractive index distribution having a concentration distribution in La was obtained. When this glass was cut and the optical characteristics were measured, it showed the optical characteristics as shown in FIG.
It was found to have effective optical characteristics.

[0040]

Example 4 106.9 ml of Si (OC ₂ H ₅ )
To _{4, 1-C 3 H 7} OH and 6.3ml of 104.7ml
2N HCl aqueous solution was added for partial hydrolysis.
After that, 67.6 g of Zr (OnC ₄ H ₉ ) ₄ and 4
A mixed metal alkoxide solution was prepared by adding 4.9 ml of 1-C ₃ H ₇ OH and further stirring for 1 hour to form a mixed metal alkoxide having a Si—O—Zr bond. Next, to obtain a wet gel by the addition of hydrochloric acid prepared by dissolving YbCl ₃ · 6H ₂ O in 115 g. This wet gel was immersed in an aqueous solution of sodium oxalate. After drying at 80 ° C, 145
Bake to 0 ° C, 55SiO ₂ · 17ZrO ₂ · 26
A transparent glass having a composition of Yb ₂ O ₃ · 2Na ₂ O (mol%) was obtained.

[0041]

Example 5 21.1 ml of Si (OC ₂ H ₅ ) ₄ and 4
Mix 3.1 ml 1-propanol, then 1.7 m
1 / 100N HCl aqueous solution was added and stirred for 60 minutes to partially hydrolyze, and then 1.5 g of Al (Osec
-C ₄ were H ₉₎ and stirred _{2 (C 6 H 8 O 3} ) 60 minutes added. Next, 16.3 ml of 1N-HCl in which 2.41 g of Nd (C ₅ H ₇ O ₂ ) ₃ was dissolved was added and stirred, and then the mixture was poured into a polypropylene beaker for gelation to obtain a wet gel. The wet gel was aged at 60 ° C for 7 days, immersed in lactic acid, and then immersed in methanol to 40
When dried at ℃ and baked to 1400 ℃, it was 95SiO ₂ · 2.5Al ₂ O ₃ ·
A glass having a composition of 2.5 Nd ₂ O ₅ (mol%) was obtained. When the fluorescence characteristics of this glass were measured, it was 720
A laser transition could be observed for excitation light near 830 μm. Further, when laser oscillation was performed at 1.06 μm, oscillation was possible.

[0042]

EXAMPLE 6 125.7 ml of Si (OCH ₃ ) ₄ containing 51.1 g of Ti (OnC ₄ H ₉ ) ₄ was added to 350
ml ethanol and 45.5 g Al (Osec-
300 ml of 1 / 100N HCl aqueous solution in which 30.4 g of Tm (HCOO) ₃ was dissolved in C ₄ H ₉ ) ₃ was added to hydrolyze, and gelled in a glass container having an inner diameter of 20 mm to prepare a wet gel. did. The wet gel was aged at 40 ° C., immersed in a citric acid solution, dried at 100 ° C., and fired at 400 ° C. in an oxygen atmosphere to obtain a porous glass. Further, this porous glass is treated with Tm (NO ₃ ) ₃
After being dipped in the ethanol solution described above to impregnate the pores, it was dipped in a solution of maleic acid. Then, the gel was dried at 50 ℃, 56.5SiO ₂ · 1 and fired to 1420 ° C.
5TiO ₂ · 18.5Al ₂ O ₃ · 10Tm ₂ O ₃ (m
ol%) composition glass was obtained. When the fluorescence characteristics of this glass were measured, laser transition could be observed, and when laser oscillation was performed, oscillation was possible.

[0043]

EXAMPLE 7 Si (OCH ₃ ) ₄ 30 ml, Si (OC
₂ H ₅ ) ₄ 30 ml and triethyl borate 12.4
25 ml of an aqueous hydrochloric acid solution having a pH of 2 was added thereto and stirred for 1 hour to carry out a partial hydrolysis reaction. Here, 107.63 m of 1.25 mol / l lead acetate aqueous solution
1 and 15.35 ml of acetic acid were added, and the resulting sol was mixed vigorously and the resulting sol was dispensed and then gelled. This gel was immersed in a lead acetate isopropanol-water mixed solution,
After strengthening the gel, it was immersed in an isopropanol-acetone solution to precipitate and fix lead acetate microcrystals. Then, the gel containing lead acetate microcrystals was immersed in a potassium acetate ethanol solution for 6 hours to distribute the lead acetate concentration in the gel such that the lead acetate concentration was high in the central portion and low in the peripheral portion. This gel was sequentially dipped in a mixed solution of 5: 5 acetic acid 0.01N-isopropanol / acetone in a volume ratio of 5 and acetone to fix the distribution, dried and then fired to 620 ° C. to obtain a colorless transparent glass. It was The shape of the refractive index distribution of the obtained glass had a wide range of applications without having an inflection point as shown in FIG.

[Comparative Example 2] A gel prepared by carrying out the procedure up to the step of imparting distribution in the same manner as in Example 7 had a volume ratio of acetic acid-free isopropanol / acetone of 5: 5 at the time of subsequent fixation. A glass was obtained by immersing the mixed solution and acetone in that order, drying and sintering. Since the distribution shape of lead acetate in the glass was distorted, the refractive index distribution shape was also distorted at the peripheral portion, and this glass element had a problem in its characteristics in optical design.

[0045]

Example 8 A gel prepared in the same manner as in Example 7 was dipped in a lead acetate isopropanol-water mixed solution to strengthen the gel, and then dipped in an isopropanol / acetone mixed solution to obtain lead acetate microcrystals. Precipitated and fixed. A gel containing fine crystals of lead acetate was immersed in a potassium acetate ethanol solution for 2 hours to distribute the lead acetate concentration in the gel such that the lead acetate concentration was high in the central part and low in the peripheral part. Immerse this gel in isopropanol / acetone mixed solution, and after 1 hour,
An ol / l acetic acid-acetone solution was added dropwise at 1.2 ml / h. After drying the thus fixed distribution gel, 6
The transparent and colorless glass was obtained by baking to 20 ° C. The refractive index distribution shape of the obtained glass has a wide range of applications without having an inflection point.

Regarding the method for producing a multi-component glass, the glass has been fired in the above, but it is not always necessary to make it non-porous depending on the application, and the production of porous glass is also limited in principle. Not something. Also,
Applicable elements are not limited to those shown in the examples, and if the acid dissociation constant of a metal ion with an organic acid or an organic acid salt is sufficiently small, there is no limitation in principle. Not a thing.

[0047]

【The invention's effect】 As described above, the method for producing the glass of the present invention
According to the method, it is dissolved in the pores of the wet gel, which is a porous body.
The metal salt present in the form of a crystalline organic metal salt
Uniformly deposit in the pores and deposit a large amount to ensure that
A multi-component glass that can be fixed and contains various elements
Glass having a refractive index profile with a specific density and concentration profile
Can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a process drawing showing steps of a manufacturing method for manufacturing glass via a porous body.

FIG. 2 is a graph showing the concentration distribution of the metal component in the gel immediately after giving the concentration distribution to the metal component.

FIG. 3 is a graph showing a concentration distribution of a metal component in a gel when a concentration distribution is given to the metal component and fixed by a conventional method.

FIG. 4 is a characteristic diagram showing optical characteristics of glass having a refractive index distribution obtained in Example 3 of the present invention.

FIG. 5 is a graph showing a radial direction refractive index distribution of glass having a refractive index distribution obtained in Example 7 of the present invention.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03B 8/00-8/04 G03B 37/014

Claims (6)

(57) [Claims] 1. Pores formed by using a metal alkoxide
In producing a multi-component glass via a wet gel that is a substance, in the step of fixing the metal component in the wet gel, a compound selected from an organic acid or an organic acid salt is added. a solution containing at least one, the metal salt by immersing the wet gel containing in solution in a solvent in the pores, the wet gate said metal salt is precipitated in the pores as crystallites of organometallic salt
A method for producing glass, characterized in that the glass is fixed in the glass. 2. Pores formed by using a metal alkoxide
In producing a multi-component glass via a wet gel that is a substance, in the step of fixing the metal component in the wet gel, a compound selected from an organic acid or an organic acid salt is added. A wet gel containing a metal salt dissolved in a solvent in a pore is immersed in a solution containing at least one kind to precipitate the metal salt in the pore as a fine crystal of an organic metal salt. To
The wet microcrystalline the wet gel of the gel the solubility of the metal component is immersed in a solvent miscible with low and water the organic metal salt
A method for producing glass, characterized in that the glass is fixed inside . 3. Pores formed by using a metal alkoxide
In producing a glass having a refractive index distribution via a wet gel that is a substance, after giving a concentration distribution to the metal component, in the step of fixing the concentration distribution, the solubility of the metal component is low and water and A solution containing at least one compound selected from an organic acid or an organic acid salt in a solvent to be miscible, containing the above-mentioned concentration distribution and containing a metal salt in the pores in a state of being dissolved in the solvent in the pores The method for producing glass, wherein the wet gel is dipped, and the metal salt is precipitated in the pores as fine crystals of an organic metal salt and fixed in the wet gel . 4. Pores formed by using a metal alkoxide
In producing a glass having a refractive index distribution via a wet gel that is a substance, after giving a concentration distribution to the metal component, in the step of fixing the concentration distribution, the solubility of the metal component is low and water and A solution containing at least one compound selected from an organic acid or an organic acid salt in a solvent to be miscible, containing the above-mentioned concentration distribution and containing a metal salt in the pores in a state of being dissolved in the solvent in the pores wet gel was immersed was, the metal salt is deposited in the pores as crystallites of organic metal salts, then the by immersing in a solvent the wet gel solubility of the metal component miscible with low and water concentration Wetting gel of fine crystals of organometallic salt with distribution
A method for producing glass, characterized in that the glass is fixed inside . 5. The concentration of a solution containing at least one compound selected from the organic acids or organic acid salts is changed with time .
The method for producing glass according to any one of items . 6. The organic acid or organic acid salt selected from the above.
Compounds include acetic acid, citric acid, malic acid, maleic acid,
At least one of oxalic acid, lactic acid, and salts thereof
Any one of claims 1 to 4, characterized in that
The method for producing glass according to Item 1.