Bioglass films were prepared by reactive magnetron sputtering from a 45S5 target and than annealed in air up to 550 oC in order to relax the mechanical stresses. The mixtures (0, 7 and 15%) of oxygen and argon were used in order to modify the films stoichiometry. Morphological and compositional studies were performed by SEM coupled with an EDAX system. FTIR and micro Raman measurements were performed in order to investigate the molecular vibrations of the BG structure. A modified composition respect to the target one was found for all the films, with lower silicon dioxide concentrations. The films displayed rough surfaces with spherical particles of 10-20 μm diameter embedded in the surfaces. The Raman results evidenced important carbonate lines besides the silica-phosphate bands.