Ultraviolet (UV)-curing behavior of an epoxy acrylate resin system comprising an epoxy acrylate oligomer, a reactive diluent, and a photoinitiator was investigated by Fourier transform infrared (FTIR) spectroscopy. The conversion changes of the resin system containing 20 phr of 1,6-hexanediol diacrylate as a reactive diluent and 2-hydroxy-2-methyl-1-phenyl-propan-1-one as a photoinitiator were measured under different UV-curing conditions. The fractional conversion was calculated from the area of the absorption peak for the vinyl group vibration occurring at 810 cm(-1). The effects of photoinitiator concentration, total UV dosage, one-step or stepwise UV irradiation, UV intensity, atmosphere, and temperature on the curing behavior of the resin system were investigated. The conversion of the resin system increased rapidly at the initial stage of the UV-curing process but increased very slowly after that. The final conversion of the resin system was mainly affected by total UV dosage. (c) 2005 Wiley Periodicals, Inc.