Abstract: An electrochromic cell is provided having a Li.sup.+ doped oxymethylene-polyoxyethylene solid polymer electrolyte. The film of ionically doped oxymethylene-polyoxyethylene is sandwiched between two complementary electrochromic layers, one of which is tungsten oxide. The other electrochromic layer is a polyaniline or a Prussian Blue material. The complementary electrochromic layers are deposited onto electrically conductive transparent substrates, such as fluorine-doped tin oxide coated glass. The electrochromic cell colors and bleaches by the application of an appropriate electrical potential between the two electrochromic films. The Li.sup.+ doped oxymethylene-polyoxyethylene electrolyte is stable at elevated temperatures up to about 100.degree. C.

Abstract: A method is disclosed for forming a tungsten oxide film on a substrate by applying an alkyl amine tungstate compound thereon and removing at least a portion of the alkyl amine tungstate compound to form a tungsten oxide film.In a preferred embodiment, a solution of alkyl amine tungstate compound is formed in a solvent to uniformly apply the alkyl amine tungstate compound; the solvent is removed by evaporation thereby forming a deposit; the deposit is heated for a time and at a temperature sufficient to at least partially pyrolyze the alkyl amine tungstate compound.The alkyl amine tungstate compound desirably may be selected from the group consisting of bis (di-n-octylammonium) tetratungstate, and di (n-octadecylammonium) tetratungstate. Preferably, bis (di-n-octylammonium) tetratungstate is used.The invention also provides tungsten oxide films which include suboxides of tungsten oxides (WO.sub.