Editors : M.J. Hampden-Smith, W.G. Klemperer, C.J. Brinker
a1 Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802
Silicon oxycarbide gels and glasses were synthesized using various ratios of methyldimethoxysilane and TEOS. These gels and glasses were compared with those made from methyltrimethoxysilane and TEOS. The effect of the Si-H functionality in the methyldimethoxysilane was of primary interest. Hydrolysis and condensation processes were monitored using 1H and 29Si-NMR spectroscopy. The structures and the oxycarbide fractions of the glasses, obtained after heating the gels to 900°C in flowing argon, were investigated with 29si-MAS NMR. The total carbon and silicon contents of the glasses were determined using chemical analysis. The glasses covered the range of carbon concentration from ∼1 to 15%, while the silicon concentrations were constant at about 40%. The concentration of the oxycarbide species was enhanced in the glasses synthesized with the Si-H functionality in the precursor.