When the size of the inorganic domains in a polymer composite are reduced to nano-scale dimensions, the term nano-composites or organic-inorganic hybrids is used to differentiate them from conventional (micro-)composites. Organic–inorganic hybrids are characterised by a morphology in which the two phases are co-continuously dispersed. The inclusion of a nano-sized inorganic phase in an organic matrix, can be brought about by either the addition of pre-formed nanoparticles or by the sol–gel method. The second method is used for the production of hybrids (also known as ceramers). In this study the nano-composites were obtained by casting solutions of epoxy resin and silica precursors both from in-situ generated silica by sol–gel using TEOS in appropriate conditions and as pre-formed dispersions of 7nm diameter silica particles.