In this work, we present experimental observations of radiation damage in thermal SiO2 films grown on silicon, induced by energetic (> 0.2 GeV) O, Ni and Xe ions bombardement. The structural analysis of the SiO2 films, using infrared absorption spectroscopy, ellipsometry and etch rate measurements, points to atomic displacements, broken and strained Si-O bonds induced by irradiation. We have also estimated the damage production cross section and the track radii of the ions in the amorphous SiO2 films as a function of the electronic stopping power.