Thermo-physical and mechanical properties of partially and completely cross-linked RTM6 epoxy resin samples in the glassy state have been investigated. A significant dependence of glass transition temperature, density, and modulus on the curing history and the curing degree is found. Density and modulus decrease with increasing curing degree and show a step-like irregularity in the so called transition region, which is related to the transition from rubber to glassy state during cross-linking and the starting of structural relaxation processes. The relationship between the thermo-physical and mechanical properties, which is important for the development of new processing routes for fiber reinforced polymers, is addressed. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4338-4346, 2013