The photoinitiated radical copolymerization of difunctional vinyl ether/unsaturated polyester containing maleate has been studied by differential photocalorimetry. The copolymerization kinetics were found to be affected by various factors, such as the composition, the photoinitiator concentration, the light intensity and the presence of oxygen. No temperature effect on the copolymerization was found. The mixture of vinyl ether and unsaturated polyester containing maleate was studied by fluorospectrophotmetry and the existence of a complex of electron donor-acceptor was detected.