Thin film characterization techniques such as Fourier transform infrared spectroscopy and ellipsometry and thermal analysis techniques such as differential scanning calorimetry, thermogravimetric analysis, and dielectric thermal analysis were used to monitor the thermal curing of hydrogen silsesquioxane. This study gives evidence which support the notion that the redistribution of Si-O and Si-H bonds is the reaction mechanism responsible for the chemical changes induced by hearing. Curing of hydrogen silsesquioxane is found to be accompanied by weight loss, dimension change, and change in dielectric properties. A three-stage curing process has been postulated based on the data collected.