In the present study, the kinetics of copolymerization reaction of propylene oxide (PO) and butylene oxide (BO) with glycidyl methacrylate (GMA) in the presence of BF3 · O(C2H5) 2 catalyst were investigated. The kinetic parameters and activation energy of the copolymerization reaction were calculated. The amounts of reacting PO, BO, and GMA during copolymerization were determined by chromatographic method, because the same copolymerization conditions were carried out for them. It was determined that the copolymerization rate of PO (r0) and BO (r0) was higher than that of GMA, but activation energy (E) of GMA was higher than that of PO and BO. The rate of reaction, the rate constant, and activation energy were calculated from the amount of copolymer obtained with respect to time. The structures of synthesized copolymers were determined by the spectral and chemical analysis methods. © 2007 Wiley Periodicals, Inc.