The technique of Fourier transform infrared reflection-absorption (FTIR-RA) spectroscopy has been successfully adapted to the study of bulk and interfacially activated photodegradation of several types of polymers on various metallic substrates. The technique enables qualitative and quantitative study of photochemical reaction mechanisms and rates. A controlled Environmental Exposure Chamber (CEEC), which permits collection of IR-RA spectra of the polymer/metal samples during their exposure to controlled spectral distributions of UV, temperatures, and gas mixtures, was built into the sample compartment of a Nicolet 7199 FTIR spectrophotometer. Surface analysis, gel permeation chromatography (GPC), UV spectroscopy, and UV spectroradiometry were used to complement the FTIR-RA results.