FORFARANDE FOR FRAMSTELLNING AV ETT GLASALSTER MED KISELDIOXIDRIKT YTSKIKT

摘要

A method for producing a glass article which comprises melting and forming a preshaped glass article having a composition in the phase separable regions of the alkali-boro-silicate or alkali-boro-germania-silicate systems, inducing the article to phase separate, leaching out a silica-poor phase from the surface layers only to form a structure having porous surface layers surrounding a solid region of substantially the original glass composition, washing this structure with an organic media which dissolves oxides of boron and other leaching reaction products, drying and heating to collapse the outer porous structure to form a glass having a silica-rich surface layer surrounding a solid region having substantially the original glass composition. The method substantially reduces the breaking tendency. A glass material and preshaped glass articles are also disclosed.