Annihilation kinetics of color center in polycarbonate (PC), irradiated with gamma ray at elevated temperatures, was investigated. The transmission loss in the PC was monitored in the ultraviolet and visible wavelength range. The transmittance decreased with increasing gamma-ray dose. The loss was attributed to the presence of annealable and permanent color centers. The absorbance in situ data were detected at the wavelength of 450 nm and found in good agreement with the theoretical model in which the annealable color center followed a first-order kinetic process. The rate constant satisfies the Arrhenius equation, with the activation energy of the color centers decreasing with increase of the gamma-ray dose. The results were compared with the early findings reported in the literature. POLYM. ENG. SCI., 2012. (C) 2012 Society of Plastics Engineers