High molecular weight poly [epichlorohydrin-co-(ethylene oxides)] [P(EH/EO)s] composed of high ethylene oxide (EO) content were synthesized by a coordination anionic polymerization of epichlorohydrin (EH) and FO and were used as matrixes for polymer solid electrolytes. The glass-transition temperature of P(EH/EO)s was linearly shifted to the low temperature with the increase of EO content. The melting temperature attributable to the EO crystalline phase was detected in P(EH/EO)s having EO units of >81 mol %, but their heat of fusion was small. The temperature dependence of ionic conductivity of the P(EH/ EO)s doped with LiClO4, was expressed by WLF equation. P(EH/EO), whose EO content was 81 mol %, showed the highest ionic conductivity at 30degreesC when LiClO4, was doped in the concentration of [Li]/[-O-] = 0.05, and it was 2.2 X 10(-5)S/cm at 30degreesC. (C) 2004 Wiley Periodicals, Inc.