Reaction of Dehydrated Surface of Partially Leached Glass with Water

Abstract

Glasses containing sodium and potassium were leached with water and the alkali was extracted by a linear relation with square root of time. The leached surfaces were then dried by different techniques, heat‐treated at various temperatures, and again attacked by water. For glasses containing Na2O, the heat‐treated preleached grains showed neither extraction behavior having a linear relation with time nor extraction by a square root‐time relation. For glasses containing K2O, the heat‐treated preleached glass grains showed a linear relation of extraction. The results were explained by a structural transformation for the sodium glasses, in which an S‐shaped sodium ion distribution at the surface layer was greatly affected by the heat treatment. For the potassium glasses no such transformation could occur since the alkali ion distribution was exponential and unaffected by temperature.