Photoinitiating behaviors of bis[4-(2-hydroxyisopropionyl)]ether photoinitiator on free-radical polymerization have been investigated. The kinetics of photopolymerization initiated by the photoinitiator was studied by means of differential photocalorimetry. The bifunctional photoinitiator showed comparative performance with those commercial photoinitiators with monofunctional chromophoric group. The effect of UV intensity on the polymerization rate was investigated, and the value of exponential factor was found to be 0.5 at the beginning of polymerization, suggesting that the photopolymerization initiated by bis[4-(2-hydroxy-isopropionyl)] ether followed biradical termination mechanism. Photosensitizer triethylamine improves the initiating efficiency while oxygen is shown to restrict polymerization in this system. (c) 2006 Wiley Periodicals, Inc.