Films of an organic-inorganic nanocomposite material formed by a polymeric matrix (ethylene-vinyl alcohol copolymer-EVOH) and nanometric TiO2 particles (ca. 10 nm) have been obtained with photo-catalytic properties in the elimination of pathogens. Optical spectroscopy experiments have been performed in order to characterize the films and evaluate their properties as a function of TiO2 doping in the range between 0.25 and 13 wt%. Anatase TiO2 nanoparticles seem to be well-dispersed up to 2% but aggregation for higher doping originates the two different regimes observed in the acoustic modes as well as in the optical absorption in the visible spectral range. (C) 2007 Elsevier B.V. All rights reserved.