c aminofunctional siloxane having the average formula: ##STR25## (C) 0.1 to 10 weight percent of a compound having the average formula: ##STR26## wherein Me denotes methyl, R is independently a monovalent hydrocarbon radical having from 1 to 6 carbon atoms or an aryl radical, R1 is a group having its formula selected from the group consisting of ##STR27## and wherein R3 is a divalent hydrocarbon r