JPS56155033A - Preparation of porous glass - Google Patents

Abstract

PURPOSE:To prepare a porous glass having enlarged and improved micropores, by eluting the soft phase of a glass having the phase separation with an acid, filling a low-reactive etching solution in the micropores, and replacing the solution with another solution or heating the glass to a higher temperature to increase the reactivity of the etching solution to dissolve the glass surface in the micropores. CONSTITUTION:A glass of specific composition is heated to separate the glass into the soft and the rigid phases, and then immersed in an acid, e.g. a solution containing KCl in 1-5N hydrochloric acid, to elute the soft phase and prepare a porous glass. The resultant glass is then washed with water and a less reactive etching solution is introduced into micropores or a reactive etching solution is introduced into the micropores in a short time. The solution in the micropores is then replaced with another solution or the reactivity of the etching solution is increased by increasing the temperature to accelerate the dissolving reaction of the inner surface by the solution. The porous glass after the dissolving treatment is then washed with hot water, etc. to give the aimed porous glass product.