| abstract |
Described are novel photochromic heterocyclic fused indenonaphthopyran compounds having a substituted or unsubstituted heterocyclic ring fused to the g, h, i, n, o or p side of the indenonephthopyran. These compounds may be represented by either of graphic formulae (I), (I'). Also described are polymeric organic host materials that contain or that are coated with such compounds. |