benzophenone 2 benzotriazole Ar HO H 0 N)=-N '\ N /Ar H Ai

Oxanilides (see Fig. 1,4) such as Sanduvor VSU (Sanduvor is a trademark of the Clariant Corporation) are generally asymmetrically substituted with an alkyl aryl group at one end and a 2-alkoxy aryl group at the other. This results in a broad absorption spectrum with a maximum near 300 nm (8"" 15,000).