SiOC glasses produced from silsesquioxanes by the aerosol-assisted vapor synthesis method

Abstract

In this paper, we describe a new method based on aerosol-assisted vapor synthesis for making glass materials by pyrolysis of readily available silsesquioxanes CH3Si(OCH3)3 and CH3Si(OC2H5)3. Combined powder X-ray diffraction (XRD) and spectroscopic studies in the far infrared region (FIR) showed that under applied conditions the method yielded amorphous materials. Subsequent structural studies with the application of the (29)Si and (13)C MAS NMR, Raman, and middle infrared (MIR) techniques led to the conclusion that the pyrolysis of the silsesquioxane precursors resulted in glass materials with a structure of amorphous silica v-SiO2. In the case of certain glasses prepared from CH3Si(OCH3)3, they were also shown to possess in the structure some Si-C bonds (black glasses), whereas those originated from CH3Si(OC2H5)3 were composites that in addition to the silica glass phase contained domains of free/unbound carbon.