Visible photosensitizers for photopolymerizable compositions

A compound suitable for use as a sensitizer in photopolymerizable compositions, said compound selected from the group consisting of:

• ##STR8## wherein:
• R.sub.1 and R.sub.2 are independently alkyl from 1 to 4 carbon atoms;
• R.sub.3 and R.sub.4 are independently hydrogen, alkyl of 1 to 6 carbon atoms, or alkyoxyl of 1 to 6 carbon atoms;
• (R.sub.5 +R.sub.7) are --(CH.sub.2).sub.2 -- or --(CH.sub.2).sub.3 --;
• R.sub.6 is hydrogen or methyl and R.sub.8 is alkyl from 1 to 6 carbon atoms, or (R.sub.6 +R.sub.8) are --(CH.sub.2).sub.2 -- or --(CH.sub.2).sub.3 --, with the proviso that (R.sub.5 +R.sub.7) and (R.sub.6 +R.sub.8) may not be --(CH.sub.2).sub.2 -- at the same time;
• and ##STR9## wherein:
• R.sub.1 and R.sub.2 are independently alkyl from 1 to 4 carbon atoms;
• X is O, S, NR.sub.14, or CR.sub.15 R.sub.16, where R.sub.14, R.sub.15, and R.sub.16 are each an alkyl group of 1 to 6 carbon atoms or substituted or unsubstituted phenyl;
• R.sub.9 is a substituted or unsubstituted alkyl group of 1 to 7 carbon atoms or substituted or unsubstituted phenyl;
• R.sub.10, R.sub.11, R.sub.12, and R.sub.13 are each independently hydrogen, substituted or unsubstituted alkyl and alkyoxyl of 1 to 6 carbon atoms, halogen, or substituted or unsubstituted phenyl;
• or (R.sub.10 and R.sub.11), (R.sub.11 and R.sub.12), or (R.sub.12 and R.sub.13) are joined to form a six-membered substituted or unsubstituted aromatic ring.