Generalized two-dimensional (2D) correlation spectroscopy and evolving factor analysis (EFA) have been applied to the study of cationic curing reaction of mixtures of diglycidyl ether of bisphenol A (DGEBA) and gamma-valerolactone ( gamma-VL). The reaction has been monitored by Fourier transform infrared spectroscopy. The reaction periods in which a chemical change takes place are identified using EFA and then the sequence of changes are established by means of the interpretation of the synchronous and asynchronous spectra obtained with 2D correlation spectroscopy. By combining this information, in the curing process, four reactions have been detected: (1) DGEBA and gamma-VL reaction to obtain a spiroorthoester intermediate, (2) homopolymerization of DGEBA, (3) copolymerization of DGEBA with the spiroorthoester intermediate, and (4) homopolymerization of the spiroorthoester. (c) 2008 Wiley Periodicals, Inc.