| abstract |
Described are novel reversible photochromic 2H-naphtho[1,2-b]pyran compounds, examples of which are compounds fused on the naphtho-portion of the naphthopyran ring with an indeno group or certain heterocyclic substituents. Certain substituents are also present at the 2 and 5 positions and sometimes at the 6 position of the naphthopyran ring. Also described are organic host materials that contain or that are coated with such compounds. Articles such as ophthalmic lenses or other plastic transparencies that incorporate the novel naphthopyran compounds or combinations thereof with complementary photochromic compounds, e.g., spiro(indoline) type compounds, are also described. |