at least one photosensitizer which is effective to promote free radical polymerization through bimolecular photochemical reactions of the energy donor type, {HEAD ~ the hydrogen abstraction type}, or by formation of a donor acceptor complex with {TAIL ~ monomers} or additives leading to ionic or radical species; and 
at least one photosensitizer which is effective to promote free radical polymerization through bimolecular photochemical reactions of the energy donor type , { HEAD ~ the hydrogen abstraction type } , or by formation of a donor acceptor complex with { TAIL ~ monomers } or additives leading to ionic or radical species ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH