Patent ID: 8023171

Claim:
An electrochromic device comprising a cathodically coloring electrochromic composition with excellent color characteristics and durability, which composition comprises an electrically active, cathodically coloring polymer and a non-electrically conductive binder polymer in a weight ratio of cathodically coloring polymer to binder polymer of from about 1:99 to about 99:1, wherein the binder polymer is selected from crosslinked or non-crosslinked acrylate, acrylamide, polyester, polyimide, polyurethane, polyolefin, polyvinyl alcohol, epoxy and fluoro polymers and wherein the cathodically coloring polymer is of formula II wherein X is an electron poor aromatic unit selected from substituted or unsubstituted benzothiadiazole, thiadiazoloquinoxaline, quinoxaline, thienothiadiazol, thienopyrazine, pyrazinoquinoxaline, benzobisthiadiazole and thiadiazolothienopyrazine; E is a substituted or unsubstituted thiophene; Z is a substituted or unsubstituted dioxythiophene; q and r are 0, 1, 2 or 3 and R 10 , R 11 , R 12 and R 13 are the same or different and are a linear or branched aliphatic carbon chain that optionally comprises one or more heteroatoms.