A new hybrid organic-inorganic material is obtained by the in situ pol
ymerization of titanium isopropoxide in polyvinylacetate. The hydrolys
is and condensation reactions of the alkoxide are carried out in a tet
rahydrofuran solution, via a controlled sol-gel process which yields m
acroscopically homogeneous and transparent films. Small angle X-ray sc
attering allows for the determination of a composite structure of the
films, i.e., a dispersion of 'titanium oxide' particles in the organic
polymer matrix. The crosslinked nature of the resulting compounds is
shown. Thus strong interactions exist between the polymer and the inor
ganic phase, avoiding a macroscopic phase separation. Those interactio
ns are proved to be covalent links; it is therefore possible to crossl
ink chemically the thermoplastic polymer with the inorganic phase. Dyn
amical mechanical spectroscopy reveals the existence of two relaxation
s which might account for an interphase between polyvinylacetate and t
itanium oxide clusters.