Boria effects on accelerated SiC oxidation kinetics were investigated by conducting thermogravimetric analysis on SiC substrates coated with sol-gel derived borosilicate glass isothermally exposed to dry O-2 and argon at 800 degrees C and 1200 degrees C for 100 hours. Boria concentrations in the glass coatings were 0, 14-38, and 92-94 mol%, balance silica. Accelerated weight gain was observed for SiC exposures in dry O-2 at 800 degrees C when boria concentrations were >= 92 mol%, corroborated by oxide thickness ranging from 3.5 to 10 mu m. The oxide thickness predicted for pure SiC exposed to these conditions in the absence of boria is 0.15 mu m. Microstructural analysis of SiC surfaces after oxide removal revealed that boria etched the underlying SiC substrate. Oxidation exposures at 1200 degrees C in dry O-2 suppressed boria effects on accelerating SiC oxidation kinetics due to rapid boria volatilization coupled with the formation of a protective thermally grown silica scale. Accelerated weight gain or oxide growth did not occur with argon exposures at either temperature. A new mechanism for boria-accelerated SiC surface-reaction kinetics is presented based on evidence for boria etching of SiC.