wherein each R1 is, independently, an alkyl group of from 1 to 4 carbon atoms, E is a monovalent organic group containing at least one epoxy group, G is an ???(R2)bO(C2H4O)c(C3H6O)d R 3 group in which R2 is a divalent organic group, R3 is hydrogen or a monovalent hydrocarbon group, acyl group or monoester carbonate group, b is 0 or 1, c is from 0 to about 50, d is from 0 to about 50 and the sum of