Chemiluminescence emission spectra of polypropylene pellets pre-irradiated in air with c rays were measured using a time-dependent multichannel Fourier-transform chemiluminescence spectrometer. Spectra were detected immediately after heating the irradiated polymer at 150 degrees C, which was not the case for the virgin material, and deconvoluted into emission bands by least-squares fitting using Gaussian curves. The peak intensity of the initial emission band around 490 nm rapidly increased and then decreased with a constant peak wavelength during the thermal oxidation time between 0 and 10 min. We have elucidated the emission mechanism from the dependence of gamma-irradiation dose on the peak intensity. (C) 2013 Elsevier B. V. All rights reserved.