The reaction of glycidyloxydimethylphenyl silane with aniline was used as a model system to study the reactivity of silicon-based epoxy monomers. The reaction was monitored online by near-infrared spectroscopy, and the evolution of the concentration of each species throughout the reaction was determined by the application of multivariate curve resolution/alternating least squares to the set of recorded spectra. The reactivity was evaluated by a comparison of the concentration profiles obtained for the glycidyloxydimethylphenyl silane/aniline system with those of phenylglycidyl ether/aniline as a reference system. The results confirmed that the reactivity of the silicon-based epoxy monomer was higher and that its ring opening reaction was faster because of electronic effects. (c) 2006 Wiley Periodicals, Inc.