Polyaniline films on silicon and ceramic supports were prepared in situ during the oxidative polymerization of aniline. The films were heated up to 500 degrees C in an inert nitrogen atmosphere. The changes in molecular structure during the carbonization have been studied by infrared spectroscopy and Raman scattering using 514, 633 and 785 nm laser excitation lines. The transformation from polyaniline salt to the base form has been detected above 100 degrees C. The conversion to nitrogen-containing carbon-like material followed above 200 degrees C. The molecular structure of the films produced during heating to 500 degrees C contains crosslinked phenazine-like and oxidized quinonoid units. The aniline oligomers deposited on the support in the early stages of aniline oxidation are stable during heating as it has been observed by resonance Raman scattering using 785 nm laser excitation line. The water contact angles changed after carbonization, and the films became more hydrophilic as carbonization progressed. (C) 2012 Elsevier B. V. All rights reserved.