The present invention relates to asymmetrical siloxy compounds of the formulae ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group consisting of alkoxy radicals having from 1 to 8 carbon atoms; R.sup.4 is selected from the group consisting of alkylene groups having from 1 to 15 carbon atoms and arylene and alkyl substituted arylene groups having from 6 to 10 carbon atoms; R.sup.5 is selected from the group consisting of alkylene groups having from 1 to 15 carbon atoms, arylene and alkyl substituted arylene groups having 6 to 10 carbon atoms; y is 2 to 8; X is selected from the group consisting of ##STR2## W is selected from the group consisting of ##STR3## and Z is 1 to 8