Process for the production of condensation products which can be converted into glass

摘要

A process is described for the production of condensation products which can be converted into glass, in which at least one silicon compound which can be hydrolyzed to form SiO2, at least one compound which can be hydrolyzed to form Al2O3, B2O3 or TiO2 and at least one hydrolyzable alkali metal compound or alkaline earth metal compound is brought into contact with at least the stoichiometrically necessary amount of water. The hydrolysis is carried out according to the invention in the presence of a complexing agent selected from the group consisting of beta -carbonyl carboxylic esters and C2 to C5 carboxylic acids and their carboxylate ions, which prevents precipitates of hydrolysis products of the very reactive aluminum and boron compounds forming while the less reactive silicon compounds remain unchanged or are only partially hydrolyzed. After drying, the condensation products prepared in this way can be sintered with thermal compaction to form glass without it being necessary at the same time to significantly excede the glass-transition temperature of the particular glass.