The present invention relates to asymmetrical siloxy compounds of the formula wherein R1, R2 and R3 are independently selected from the group consisting of alkoxy radicals having from 1 to 8 carbon atoms; and R4 is selected from the group consisting of substituted or unsubstituted alkylene groups having from 1 to 18 carbon atoms and arylene and alkyl substituted arylene groups having from 6 to 12 carbon atoms. The asymmetrical siloxy disulfide compounds are prepared from N-cyclohexylthiophthalimide and a mercaptoalkoxysilane.