Thermochromic films of VO2 were deposited by DC reactive magnetron sputtering on stainless steel substrate. Complex refractive indexes of VO2 were determined by ellipsometric spectroscopy (0.35-16.5 mu m) for different film thicknesses. Optical simulations were performed to model the spectral reflectance of the film/substrate system for a film thickness of 100 nm and 200 nm and to monitor the optical contrast of the thermochromic layers by comparing the spectral reflectance at 25 degrees C and 100 degrees C. The good agreement observed between experimental and theoretical spectra demonstrates the adequacy of the model for predicting the optical properties of the samples. (C) 2010 Elsevier B.V. All rights reserved.