THERMAL EVOLUTION OF GELS DERIVED FROM CH3SI(OC2H5)3 BY THE SOL-GEL METHOD

The structure change of CH3Si(OC2H5)3 (MTES)-derived gels on heating in N2 and NH3 to form C- and N-containing SiO2 glasses, respectively, was examined by IR spectroscopy and thermal analysis. The gel was considered to consist of siloxane polymers containing strained 4-fold siloxane ring structure. The SiCH3 and 4-fold rings were thermally cleaved around 700°C to form SiH, SiOH and carbonous matter in N2, and SiNH2 as well as SiH and SiOH bonds in NH3. The SiNH2 was condensed at higher temperatures, resulting in N-containing SiO2 glass. © 1990.