The extent of conversion of epoxy groups cured with diaminodiphenyl methane, a diamine, at 100 degreesC was approximately 100%, and the glass-transition temperature (T-g(i)) was found to be an increasing function of cure time with very large increases with extended postcure treatments at 180 degreesC. However, this considerable increase in the T-g with postcure at 180 degreesC was not due to the reactions of epoxy and amine groups. The specific volume reduced with the T-g to a minimum at 103 degrees for the cured samples but showed a very slight increase with the T-g for the postcured samples. It was also found that the glassy modulus (E-g) was a linear decreasing function of the T-g. There were two separate relationships between the E-g and the rubbery modulus that depended on the cure conditions and suggested that the "structure" formed due to cure at a temperature of 100 degreesC was different than that at postcure, which was 180'C. The most sensitive structural parameter for these cured epoxy resins was their T-g(i)