Most organic materials are quite opaque to IR radiation, making it nearly impossible to measure the polarization properties at these wavelengths. By placing the highly absorbing organic material on a high index of refraction prism and making use of the evanescent field present at the interface for angles exceeding the critical angle, it is possible to measure the organic material's polarization characteristics. Attenuated Total Reflection (ATR) devices have been constructed in-house for use in our IR polarimeter operating over the spectral range of 3-14 microns. Single bounce internal reflection ZnSe prisms are used in our devices to measure the polarization characteristics of highly absorbing materials. Using attenuated total reflection along with a dual rotating retarder polarimeter, it is possible to determine the full Mueller Matrix, and thus determine the linear and circular diattenuation and retardance. With this information we can determine the complex index of refraction, dichroic ratio, and isotropic ratio of materials which are opaque in the IR region. With this knowledge of the material polarization properties, it may be possible to determine the orientation of the molecules in films made of long helical organic molecules and determine the enantiomeric purity of stereo-isomers. The theoretical performance of these devices with a focus on the organic chemical applications has been determined and compared with experiments. In this paper we present a summary of the theoretical basis for the measurements and make comparisons with our measurements.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.