| abstract |
(57) [Summary]nNovel reversible photochromic 2H-naphtho [1,2-b] pyran compounds are disclosed, such as compounds wherein the naphthopyran ring is fused to the naphtho moiety by an indeno group or certain heterocyclic substituents. It is. Certain substituents are also present at the 2- and 5-positions, and in some cases also at the 6-position of the naphtho ring. Organic host materials containing or coated with such compounds are also disclosed. Also disclosed are articles such as ophthalmic lenses or other plastic transparencies that incorporate the novel naphthopyran compounds or supplemental photochromic compounds, eg, spiro (indoline) type compounds, and combinations of the compounds. |