In this study, a novel vinyl polymer containing 2,4,5-triphenylimidazole side groups was synthesized through conventional radical polymerization, which possesses the characteristic of temperature-dependent absorbance in the near-ultraviolet (UV) spectral region. The linear dependence of UV absorbance on temperature was confirmed for the polymer both in solid state and in solution by experiment and also supported by the results of theoretical investigation. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012