The thermal degradation of the system diglycidyl ether of Bisphenol A (BADGE, n = 0) and 1,2 diamine cyclohexane (DCH) was studied by thermogravimetric analysis (TG) in order to determine the actual reaction mechanism (RM) of the decomposition process. Owing to the nature of the problem, the RM cannot be ascertained without knowledge of the activation energy. The activation energy of the solid state process was determined using Kissinger＇s method, which does not require knowledge of the RM, resulting to be 144.01 kJ/mol. Different integral and differential methods and different RM reported in the literature were used and compared with this value. Also, the experimental results were compared to master plots, in the range of the Doyle approximation. Analysis of experimental results suggests that in the conversion range studied, 5-20%, the actual RM is an A(4) sigmoidal type. (C) 2000 Elsevier Science Ltd. All rights reserved.