PROCESS FOR PRODUCING OPTICAL GLASS PRODUCT

摘要

A process for producing an optical glass product having a predetermined distribution of refractive index in the interior of the product is disclosed. The process comprises the steps of: (a) preparing an aqueous silicate solution containing from about 0.1 to about 0.6 mol/liter of Si (as SiO2) comprising silicic acid and at least one element selected from the group consisting of rubidium, thallium and cesium; (b) mixing the silicate solution with aa acidic aqueous solution, and letting the two solutions react with each other for a period of time sufficient for polymerization to produce a porous gelled product wherein the silica particles are agglomerated; (c) leaching the gelled product with a liquid selected from the group consisting of water, a weakly acidic aqueous solution, an aqueous solution having an alkali metal salt dissolved therein and an aqueous solution of organic matter capable of dissolving Rb2O, Cs20, or T12O, until the center of the product starts to dissolve; and (d) drying the leached product in a predetermined atmosphere, and further heating the partially leached gelled product at a temperature sufficiently high to eliminate the particulate material but lower than the melting point of the silica.