The effluent gas-phase composition from the atmospheric pressure reaction between tetraethylorthosilicate (TEOS) and ozone was investigated as a function of reactor temperature and initial reactant molar ratio. Online, continuous quantitative determination of gas species was achieved using Fourier transform infrared techniques. TEOS decomposition was a function of initial ozone concentration and reactor temperature. Ozone enhanced TEOS decomposition was found to generate carbon monoxide, carbon dioxide, formic and acetic acids; and water, in addition to unreacted source species.