Thermal chemiluminescence spectra of polytetrafluoroethylene powder irradiated by gamma rays in air at room temperature were measured with a multichannel Fourier-transform chemiluminescence spectrometer. The luminescence appeared immediately after heating the irradiated samples at 160, 180 and 200 degrees C in dry air and in N-2 and then disappeared within a few minutes, whereas virgin samples showed no luminescence. The lifetime of luminescence decreased as the heating temperature increased, but the total amount of luminescence at each temperature was nearly constant. From this observation an emission mechanism was derived with the aid of ESR and IR spectroscopy. (C) 2014 Elsevier B.V. All rights reserved.