The UV photopolymerization of trimethylolpropane triacrylate with a photoinitiator of 2-ethylanthraquinone is monitored using the variation of resonant resistance of a quartz crystal resonator to investigate the polymerization kinetics. The roles of initiator concentration and irradiation time are experimentally examined, and it is found that two different kinetics are involved in the photopolymerization. The initiator radicals produced by the UV light proceed the polymerization as long as the monomer remains even after the UV illumination has stopped. The experimental results indicate that the photopolymerization has the first-order kinetics at the first-and the zeroth-order kinetics followed. With the high concentration of initiator the polymerization occurs in the firstorder kinetics only, and so does with long irradiation time. The polymerization constants of the first and zeroth-order kinetics are estimated from monitoring monomer amounts at different polymerization conditions. The photopolymerization is characterized with the FTIR spectroscopy. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 4578-4585, 2011