JPS60176934A - Production of glass - Google Patents

Abstract

PURPOSE:To produce homogeneous glass having uniform distribution of a dopant with a low damage ratio of porous gel, by steaming a specific porous gel, dipping the gel in a solution containing the dopant, and drying and firing the resultant gel. CONSTITUTION:A porous gel, produced from a metal compound solution, e.g. water glass, by the sol-gel method, and having open cells is steamed by exposure to an atmosphere slowly increasing the humidity finally to 90%RH to adsorb water on the surface of the gel and pores. The steamed gel is then dipped in a solution containing a dopant, e.g. CsNO3, to permeate the dopant in the form of the solution into the pores thereof. The resultant gel is then dried to deposit the dopant on the pore surfaces, and the dried gel is fired in an oxidizing atmosphere, decomposed into oxides and vitrified together with the gel substrate component.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for producing high-purity glass useful for optical and electronic devices.

[Prior art]

A solution of an oxide or a compound that decomposes or reacts to become an oxide is impregnated into the pores of porous silicate or Gelmy-F, which has internally interconnected pores, and is further dried or fired to release the dopant. Methods of producing glass bodies by deposition and subsequent firing are known. (For example, JP-A-Sho
o-2g33q) Conventionally, when producing glass by this method, for example, porous Vycor (trademark of Corning Inc.)
Porous glass, commonly called glass, has been used as a matrix. Vycor glass is known as K5
A homogeneous glass of the iG2-B203-Na20 system is made, and by heat treatment the glass is phase-separated into a part consisting of Habo5102 and a part consisting of HaboB203-Na2O, and the B203-Na2O system is separated using an acid such as hydrochloric acid. The glass is made of leached parts and is made only of 5i02. However, the porous glass obtained by this method is 10
Instead of 0% 8102 glass, about 4i% (8203
10 Na20) remains, and the pore diameter is not uniform,
For example, when leaching is performed from the base glass of a round bar, there is a drawback that the diameter of the pores in the center of the round bar becomes small. For this reason, when Vycol is used as the matrix porous glass when producing optical glass materials, for example,
A defect occurs in that the dopant distribution is non-uniform and the refractive index distribution falls off at the center of the round rod. This is because the dopant was not sufficiently precipitated due to the small pore diameter at the center of the round rod. In order to avoid this problem, for example, Japanese Patent Application Laid-Open No. 31-1989. -10Q733 VC As shown, make a large-sized porous bifur, and press the center part (where the pore diameter is small) and ream it.
After cutting the round bar to obtain a porous glass with a substantially uniform diameter, KF-Panl is precipitated in the pores and heat-treated to produce an optical glass with no distortion in the center of the round bar. I'm getting the material.

However, recently it has become possible to produce porous glass by the so-called sol-gel method. did it. According to this horn method, the diameter of the pores of porous glass can be made more uniform (41), unlike in the case of Hycor, but in order to make VC, the transition point of the glass is It must be heated to a temperature close to i-1, at which time 1) [ ] heat (,' (therefore, the pores that existed in the gel state are baked, and the pore diameter becomes small 4 [ There is a problem that +: t, s is required to precipitate a sufficient amount of donogunt into the porous pores.
This is because although a pore diameter of about 0 to 100 A is desired, the pore diameter becomes smaller due to heating of the gel.

Therefore, it is desirable to prepare a porous gel having large pores, immerse it in a solution of L-band, precipitate the compound in the pores, and then heat-treat it to obtain glass. However,
If a porous gel is immersed as it is in a solution of a compound, there is a problem that the gel will crack. It is thought that a large amount of water is adsorbed on the pore surface of the gel at once, and the porous gel breaks down due to the heat of adsorption.

[Purpose of the invention]

An object of the present invention is to provide a method for producing crow using the above-mentioned porous kell, which does not cause pea-pan 1 solution to be impregnated with the kettle.

[Achieved in Ij of the invention]

The method for producing crow of the present invention is ii produced by the Turkel method.
Is dopa/t dissolved after steam treatment of a porous gel with continuous pores? F It is characterized by soaking in hollyhocks, drying/processing, and firing.

The sol-gel method referred to in the present invention is to generate a metal compound vine from a metal compound solution, polymerize the sol to form a gel, volatilize or decompose the solvent in the gel, and obtain a porous gel. IX+ is a glass that is vitrified by firing at a humidity higher than the glass's transition point and also crushes the pores! ! It is a construction method. Specifically, there is a method known from ancient times for producing silica gel, in which acid is added to water glass while stirring to first form a sol, which is then dried to form a gel. ! ; As in No. 3'3'lq, silicon alcoholate and other metal alcoholates are mixed, water is added to cause hydrolysis, first a vine is formed, and the reaction is further advanced to polymerize into a gel. This refers to a method of producing glass from the gel.

The gel obtained by the sol-gel method contains a large amount of solvent and water, and when it is heated and dried, the solvent evaporates or decomposes and evaporates, or disappears by combustion, and then VC continuous pores remain. Dynamicization of multi-component glass using the Tsurugel method is disclosed in Japanese Patent Application Publication No. S. Zaichi 3.
! As described in No. 3'l'1, it is not possible to obtain a multi-component glass with a uniform composition by combining metal compound solutions due to the difference in reaction rate between the two.

However, since the continuous pores remaining in the porous gel are uniformly distributed throughout the gel, by precipitating the dopant of the metal compound to be added to the pore surface and vitrifying it, a homogeneous glass with a combination of various components can be produced. It is possible to manufacture

In the present invention, the steam treatment refers to exposing to an atmosphere with a relative humidity of 90% RH or higher to cause water to be adsorbed on the gel surface and the pore surface. In the sol-gel method, the resulting gel is dried under high pressure to remove the solvent, but as a result, the dried porous gel has the property of easily adsorbing water. Exposure to an atmosphere of 100% RH is likely to cause damage, so it is desirable to gradually increase the atmospheric humidity until the final VC?W degree is 90%RH or higher.Processing in this way Therefore, it is rare for cells to be damaged even if they are immersed in a solution containing a dopant.

The dose 7' of the present invention is a substance that is produced by heating the metal oxide to be added to the glass, and penetrates into the pores in the gel in the form of an aqueous solution, and precipitates on the surface of the pores by drying. When fired, it is decomposed into oxides and vitrified together with the gel base components.

Therefore, metal hydroxides and metal salts are mainly used as dopants. In the case of metal salts, nitrates are preferred in terms of solubility in water and ease of decomposition into oxides. Further, the number of metals used for the dopant is not limited to seven, but multiple types may be used.

〔Example〕

5j-(OCH3)4'#;g and CH30H73,6g
was placed in an Erlenmeyer flask, stirred ultrasonically for about 1S, and then
Then, 3 g of oooog% ammonia water was gradually added and 15 molecules were agitated using ultrasonic waves. Diameter/3 of this mixture
mm length/! ;Put in an Omm Teflon container, cover the top of the container with aluminum foil, and place in a thermostatic oven at 70°C.
After holding for an hour, make a pinhole of about 0.3mm in aluminum foil and place it in a thermostatic oven at 70°C.
After holding it for several days, a silica gel with a diameter of 7 mm and a length of 7 mm was obtained (7 mm of silica gel was obtained. Some water and alcohol remained in this gel). In order to remove this,
After slowly heating from room temperature to lOO''C at 100°C to remove water, holding in an oxidizing atmosphere at 100°C for 2 hours to burn off the alcohol, gradually heating in vacuum again to 700°C. After holding for 1 hour, the temperature was lowered to room temperature to obtain a siliceous porous gel.A solution of 100 g of O3NO3 dissolved in water isog was placed in a beaker at 300 rtJ, and a portion of the solution was heated with the previously obtained adhesive strength. The round bar of gel was hung on its side, the top of the beaker was closed with time, and the beaker was placed in a water bath and gradually heated.

After holding the temperature at 0°C for a long time to allow sufficient water vapor to adsorb into the pores of the silica gel rod, the silica gel rod was placed in the 08NO3 solution in the beaker, and the temperature of the water bath was raised to 95°C. The mixture was held for 1 hour, and the aqueous solution of 06NO3 was allowed to permeate into the pores in the silica gel rod. A round bar was taken, and 08NO3 was precipitated into the pores of the silica gel by vacuum drying at room temperature for ttg hours, heated to 1φ in vacuum, heated to 700°C, and heated to 700°C. Hold in an oxidizing atmosphere for an hour. Next, in a vacuum (/(7-3TO)) slowly
0! When the mixture was heated to 0° C./maintained for an hour and then allowed to stand at room temperature, a glass body of 5102% by weight and cs2o/3% was obtained. G in the diametrical direction of the cross section of this glass round rod
The S component was analyzed using an X-ray microanalyzer, and the O8 component was found to have a uniform concentration in the center without a decrease in concentration.

In this example, the CsNO3 solution was infiltrated into the pores of silica gel and deposited on the pore surface, and then the gel was heated at 95°C.
By immersing the silica gel in water for about 70 minutes to create a concentration gradient in the CsNO3 solution in the pores of the silica gel, and performing the same vitrification operation as in this example, 5i02 with a continuous refractive index distribution in the radial direction can be obtained. - A QS201 round bar lens can be obtained.

〔Effect of the invention〕

The crow manufacturing method of the present invention (according to the method of the present invention)
Since the dopant is precipitated in the porous gel produced by , the dopant distribution is uniform and a homogeneous glass can be obtained. 1. Breakage of the porous gel of the culm can be reduced.

Claims (1)

[Claims] A porous gel with continuous pores produced by the sol-gel method is subjected to steam treatment and then immersed in a solution containing a dopant,
A method for producing glass characterized by drying and firing.