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

• Aerosol-assisted vapor synthesis method allows to obtain amorphous SiCxOy materials from silsesquioxanes.
• 29Si/13C MAS NMR, MIR and Raman spectroscopic studies have shown that for selected silsesquioxanes the amorphous materials have v-SiO2 structure.
• MIR and Raman spectroscopic studies showed that black glasses can be obtained.

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 29Si and 13C 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.

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