For special applications of composite materials, particularly for biomedical uses, the interface between polymer and solid should have a less ordered molecular architecture in order to confer the mobility needed for reactions of ions and low molecular weight agents. Therefore, composites were obtained by controlled reaction of macromolecules, mainly polyepoxides derived from polybutadiene, with glass ceramics which are biocompatible and bioactive. Direct linking of the reacting components by covalent bonds has been demonstrated by IR and NMR spectroscopy using model reactions with silica and other oxides.