Characterization of the chemical structure and the high temperature stability of silicon oxycarbide glasses

The objectives of this thesis were to characterize the structure of the oxycarbide glasses and to study their structural evolution with temperature. The challenges encountered arose from the short range order of the structure of oxycarbide glasses. No X-ray detectable crystalline phases were found in the glasses at temperatures as high as 1400;In this thesis, oxycarbide glasses were synthesized by sol/gel processing. The precursor gels were prepared using methyltrimethoxysilane (MTMS) and propyltrimethoxysilane (PTMS) silanes. The dry gels were pyrolyzed in argon at various temperatures and converted into oxycarbide glasses. ;It has been found that the Si-C bond in the gel structure started to break upon pyrolyzing gels in argon at 600...