Diglycidyl ether of bisphenol A (DGEBA) was cured with γ‐butyrolactone (γ‐BL) with ytterbium triflate as a catalyst. The curing was studied with differential scanning calorimetry, Fourier transform infrared (FTIR), and thermomechanical analysis. FTIR studies confirmed that four elemental reactions took place during the curing process: the formation of a spiroorthoester (SOE) by the reaction of DGEBA with γ‐BL, the homopolymerization of SOE, the homopolymerization of DGEBA, and the copolymerization of SOE and DGEBA. Moderate proportions of γ‐BL produced materials with higher glass‐transition temperatures, and the curing occurred with lower shrinkage after gelation because of the polymerization of SOE, with near‐zero shrinkage during the final stages of the curing. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2794–2808, 2003

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A mixture of diglycidylether of bisphenol A (DGEBA) and ␥-butyrolactone (␥-BL) was cured in the presence of ytterbium triflate as a catalyst. The kinetics of the various elemental processes that occur in the curing process were studied by means of isothermal curing in the FTIR spectrometer. The kinetics of the contraction during the curing was also evaluated by TMA. In both cases, the kinetics was analyzed by means of isoconversional procedure and the kinetic model was determined with the so-called compensation effect (isokinetic relationship). The isothermal kinetic analysis was compared with that obtained by dynamic curing in DSC. We found that all the reactive processes and the contraction follow a surface-controlled reaction type of kinetic mechanism, R 3 .

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