The isothermal cure of an epoxy-cycloaliphatic amine system has been studied following the evolution of both glass transition temperature and conversion. A functional relationship between T-g and conversion is established. The cure reaction is satisfactorily described by a phenomenological model with parameters determined from DSC experiments. By applying the kinetic model, gelation and vitrification curves are calculated and compared with experimental times to gelation and times to vitrification determined at temperatures between 50 and 100 degrees C. The isothermal time-temperature-transformation (TTT) curing diagram including iso-T-g contours has been established.