In yet other preferred embodiments, the siloxane additive is represented by the general formula, ##STR3## in which each of R12 and R13 independently is a monovalent group selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, and heterocyclic groups, each of which, except for hydrogen, may be substituted or unsubstituted; each of B5 and B6 independently is a poly(oxyalkylene) moi