Influence of boric acid on aging of freshly prepared tetraethoxysilane-based gels

The technique for kinetic examination of polycondensation of silicon alkoxides, which allows determining the rate of reaction between ammonium molybdate and various associates of silica for systems in which hydrolysis proceeds, was modified to examine similar systems after the gel point. Aging of freshly prepared tetraethoxysilane-based gels was for the first time studied spectrophotometrically as influenced by boric acid additions. The proportions of various molecular species of silica in the examined systems at different times after the gel point were determined in terms of the kinetic model of the molybdate reaction.