Structure and Optical Property of Polymer‐Derived Amorphous Silicon Oxycarbides Obtained at Different Temperatures

Amorphous silicon carbides are prepared by pyrolysis of a polycarbosilane precursor at different temperatures between 1000° and 1400°C. The structures of the resultant materials are analyzed using X‐ray diffraction, electron paramagnetic resonance, and Raman spectroscopy. The optical properties of the SiC ceramics are investigated by measuring their absorption spectra. It is found that there is a critical temperature range, at which the structural and optical behavior varied in different ways as a function of pyrolysis temperature. The evolution in structures is discussed and the optical behavior is explained in terms of the structural evolution during pyrolysis at different temperatures.