Results of emanation thermal analysis (ETA) and thermogravimetry (TG) of hydrous titania and titania containing 10% of ruthenia measured during heating in argon from 20 degrees C to 1000 degrees C are presented. The ETA results are interpreted by comparison with the results of traditional methods such as TG, DTA, XRD, TEM, and surface area measurement. A correspondence of the results was found. The ETA made it possible to monitor microstructure changes under in-situ conditions of heat treatment of the samples. From the ETA results measured during cooling of the heated samples to selected temperatures the values of the activation energy of radon diffusion were determined in order to characterise surface annealing and compaction of samples during heating.