Spin-coated poly(o-methoxyaniline) (POMA) thin films on various substrates were investigated using spectroscopic ellipsometry (SE) in the 1.5-4.5 eV photon energy range. Spin-coating process parameters are reported (spin speed and concentration). Substrates with higher surface energy were found to increase polymer film thickness and decrease roughness. An optical model was developed using SE data along with complementary data from atomic force microscopy and UV-vis spectroscopy to obtain optical properties-refractive index n and extinction coefficient k for POMA. The model includes Lorentz oscillators for the POMA film and a Bruggeman effective medium approximation for roughness. In-plane film optical anisotropy was not observed, but a small out of plane anisotropy was detected for the polymer. (c) 2005 Elsevier B.V. All rights reserved.