Abstract: A solid, polymeric electrolyte is prepared by:1) blending:(a) a macromer of formula (I) ##STR1## wherein R =methyl, ethyl, n is an integer comprised within the range of from 2 to 20, x is an integer comprised within the range of from 2 to 5;(b) a difunctional comonomer of formula (II) CH.sub.2 .dbd.C(CH.sub.3)COO(CH.sub.2 CH.sub.2 O).sub.m --CO--(CH.sub.3)C.dbd.CH.sub.2 wherein m is an integer comprised within the range of from 2 to 5; with a molar ratio of the macromer (I) to the difunctional comonomer (II) comprised within the range of from 98:2 to 60:40;(c) an ionic compound in an amount comprised within the range of from 1 to 30% by weight;(d) an oligomer or a dipolar aprotic liquid in an amount comprised within the range of from 0 to 80% by weight;(e) a photoinitiator in an amount comprised within the range of from 0 to 10% by weight; 2) applying the above mixture on an inert support and exposing it to a source of ultraviolet light, thermal radiations, or electron beam.