Patent ID: 7595011

Claim:
A composition which is suitable as a medium in an electrochromic device, which composition comprises a) one or more solvents suitable as a medium in an electrochromic device selected from the group consisting of ketones, cyclic esters, cyclic carbonates and glycidyl ether carbonates, and one or more materials which are a functional element of an electrochromic device, b) an effective amount of one or more ultraviolet light absorbers selected from the group consisting of hydroxyphenylbenzotriazoles and tris-aryl-s-triazines, and c) an effective amount of one or more N—H or N-alkyl hindered amine light stabilizers of formula A′ wherein E is hydrogen or C 1 -C 18 alkyl, m is 1 to 4, when m is 1, R 2 is hydrogen, C 1 -C 18 alkyl or said alkyl optionally interrupted by one or more oxygen atoms, C 2 -C 12 alkenyl, C 7 -C 18 aralkyl, glycidyl, a monovalent acyl radical of a C 2 -C 18 aliphatic carboxylic acid, said aliphatic monovalent acyl radical of a C 2 -C 18 aliphatic carboxylic acid substituted by one or more hydroxy, C 1 -C 8 alkoxy, C 2 -C 8 acyloxy, carbonyl, carboxy or C 2 -C 8 alkoxy carbonyl, a monovalent acyl radical of a C 5 -C 12 cycloaliphatic carboxylic acid or a monovalent acyl radical of a C 7 -C 15 aromatic carboxylic acid, or when m is 2, R 2 is C 1 -C 12 alkylene, C 4 -C 12 alkenylene, xylylene, a divalent acyl radical of an aliphatic dicarboxylic acid having 2-18 C atoms, or a cycloaliphatic or aromatic dicarboxylic acid having 8-14 C atoms when m is 3, R 2 is a trivalent acyl radical of a C 4 -C 12 aliphatic or C 6 -C 12 cycloaliphatic tricarboxylic acid; when m is 4, R 2 is a tetravalent acyl radical of a C 5 -C 12 saturated tetracarboxylic acid.