Raman microline focus spectrometry has been utilized to record spatially resolved and spatially averaged Raman spectra from degraded poly(vinyl chloride) (PVC) sheet. Characteristics of simultaneous thermal and chemical degradation occurring in commercial polyurethane (PU)-foam-backed PVC sheet have been inferred from the observed Raman data. From a comparison of the data recorded across a section, of the sheet, the presence of PU foam is shown to increase the degradation rate of PVC. In addition, higher concentrations, higher rates of formation and longer conjugation lengths of those polyenes formed during degradation are found at the PVC/PU contact interface. This is attributed to the extra chemical degradation occurring at the PVC/PU interface due to catalysis of dehydrochlorination by amine residues in the PU.