The method according to claim 1 in which the vinyl compound has the formula ##STR44## in which (a) R1 and R2 are H or an alkyl group having 1 to 5 carbon atoms, or together form a 5 to 9 membered ring with the carbons forming the vinyl group;(b) B is C, S, N, O, C(O), O--C(O), C(O)--O, C(O)NH or C(O)N(R8), in which R8 is an alkyl group having 1 to 5 carbon atoms; (c) Ar is an aromatic group select