The physical aging of the epoxy network consisting of a diglycidyl ether of bisphenol A, m-xylylenediamine, and polyetherimide was studied by differential scanning calorimetry. The glass transition temperature and the variation of the specific heat capacities have been calculated using the method, based on the intersection of both enthalpy-temperature lines for glassy and liquid states. The apparent activation energy (E-H) was calculated using a single method that involved separate temperature and excess enthalpy dependency. All calorimetric data were compared with those obtained for the epoxy network without thermoplastic. (c) 2007 Wiley Periodicals, Inc.