The effect of environment pressure on high temperature stability of silicon oxycarbide glasses derived from polysiloxane

Silicon oxycarbide glasses (SiOC) have been produced by siloxane resin under flowing argon atmosphere at 1000 °C. Those glasses were further annealed at 1200, 1300, 1400, and 1500 °C under the pressure of 0.01 KPa and 101 KPa, respectively, to investigate the effect of environment pressure on their high temperature stability. The two series of glasses were characterized by X-ray diffraction, 29SiMASNMR, and chemical element analysis. The environment pressure plays a crucial role on high temperature stability of SiOC glasses by promoting or hindering bonds redistribution and carbothermal reductions. It can be found that SiOC glasses exhibit enhanced thermal stability in high pressure environment.