The thermal evolution process of RuO2-SnO2/Ti mixed oxide thin films of varying noble metal content has been investigated by thermogravimetry-mass spectrometry and Fourier transform infrared emission spectroscopy. The gel-like films prepared from aqueous solutions of the precursor salts Sn(OH)(2)(CH3COO)(2-x)Cl-x and Ru(OH)Cl-3 on titanium metal support were heated in an atmosphere containing 20% O-2 and 80% Ar up to 873 K. Chlorine evolution takes place in a single stage process between 5 73 and 773 K, while the decomposition of organic species like various types of carbonyls, carbonates and carboxylates occurs in two main stages between 423 and 773 K. The combustion temperature of the organic species formed decreases with the increase of the ruthenium content, indicating the catalytic effect of the noble metal. The secondary processes can significantly influence the morphology and electrochemical properties of the films when used as anodes in electrochemical processes. (c) 2006 Elsevier B.V. All rights reserved.