The effect of electron beam irradiation on the structural and optical properties of Poly-Allyl-Diglycol-Carbonate CR-39 solid state nuclear track detector was investigated. Samples from CR-39 detector were irradiated with electron beam with doses at levels between 10 and 140 kGy. The structural and optical modifications in the electron beam irradiated CR-39 samples have been studied as a function of dose using different characterization techniques such as FTIR spectroscopy, Vickers hardness, refractive index and color difference measurements. The electron beam irradiation in the dose range 25-140 kGy led to a more compact structure of CR-39 polymer, which resulted in an improvement in its hardness with an increase in the refractive index. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 3552-3557, 2010