Tungsten oxide (WO3), vanadium and nickel-hydroxide (VOxHy and NiOxHy)-films were evaporated on glass and polymeric substrates covered with indium-tin oxide (ITO). Films of nickel-oxide (NiOx) were reactively sputtered from a nickel target. In order to obtain electrochromic devices the WO3 film was used as one electrode and with a polymeric solid state electrolyte (PSSE) glued to each of the other films which served as different counter electrodes. The films for themselves and the complete devices were investigated by optoelectrochemical and other methods. The most stable device was the WO3-VOxHy system which even improved the electrochromic properties after 3 x 10(4) cycles.