The reaction enthalpy and reaction heat capacity of three aromatic epoxyamine systems have been determined with modulated temperature diffential scanning calorimetry (MTDSC), mostly in quasi-isothermal conditions, over a wide temperature range (33-140 degreesC) and for different mixture compositions. The reaction enthalpy is only slightly dependent on the epoxy-amine chemistry, from -111 to -98 kJ/mol epoxy functionality. With the model system phenyl glycidyl ether (PGE)+ aniline, the reaction enthalpy of the secondary amine-epoxy reaction step is equal to that of the primary amine-epoxy reaction. Group contributions needed to calculate the reaction heat capacity with an additivity approach are evaluated, and a new value of 37.2 J mol(-1) K-1 for the group N--H)(C)(CB) is proposed. With this group contribution, the additivity method predicts almost equal values for the reaction heat capacity of both amine-epoxy reaction steps at 298.15 K (Delta(r)C(p,prim) = 15.7 J mol(-1) K-1 and Delta(r)C(p,sec) = 14.6 J mol(-1) K-1), whereas the experimental value of Delta(r)C(p,sec) is about three times larger than that of Delta(r)C(p,prim) at 100 degreesC. These results are confirmed experimentally for PGE+aniline as a different temperature dependence of both reaction heat capacities. MTDSC therefore is potentially interesting for differentiating between reactive species in an epoxy-amine reaction, a benefit previously assigned to spectroscopic methods only. (C) 2003 Wiley Periodicals, Inc.