Abstract: Organosilicon compounds which are silanes or siloxanes characterized by the presence of silicon-bonded groups represented by the general formula ##STR1## in which R' is a divalent hydrocarbon group which may contain ether oxygen, R" represents --CHBCH.sub.2 -- or --C.sub.6 H.sub.9 B-- in which B is OH or the group ##STR2## a and n are each 0 or 1 and Y is --OH, lower alkoxy or --NX.sub.2 wherein X represents hydrogen or lower alkyl.The compounds are prepared by the reaction of an organosilicon compound having an organic substituent which contains an epoxy group, and the appropriate acid or acid chloride. They absorb ultra violet radiation and are useful as cosmetic and other sunscreen agents.