An infrared variable angle spectroscopic ellipsometer (IR-VASE) was used to study organic polymers in the infrared (2.5-14 mu m wavelength) spectral region. For the analysis of thin film polymers IR spectroscopic ellipsometry has greater sensitivity over traditional FTIR spectroscopy providing an exciting way to characterize these materials optically. The IR-VASE used in this study is of high accuracy, rotating polarizer, rotating compensator ellipsometer that uses an FTIR spectrometer as a light source. The IR-VASE was used to measure the infrared optical constants of various polymers in both solid and liquid form. These optical constants were then used to model the percentage of water in a thin film of gelatin and the percentage of residual solvent in a thin film of silicons. In addition, the IR-VASE provided a sensitive measurement of silicone chemistry and chemical changes caused by exposure to an oxygen plasma.