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Abstract

Described are novel photochromic 2H-naphtho[1,2-b]pyran compounds essentially characterized by having two adjacent moderate to strong electron donor substituents at the 8 and 9 positions or a fused heterocyclic group formed by the substituents coming together, weak to moderate electron donors at the 2 position and a rating of at least 80 in the Relative .DELTA.OD at Saturation Test. The compounds also have certain substituents at the 5 position and optionally at the 6 position of the naphtho portion of the compound. These compounds may be represented by the following graphic formula: ##STR1## Also described are polymeric organic host materials that contain or that are coated with such compounds. Optically clear articles such as ophthalmic lenses or adjacent plastic transparencies that incorporate the novel naphthopyran compounds or combinations thereof with complementary photochromic compounds, e.g., certain other naphthopyrans, benzopyrans, and spiro(indoline)type compounds, are also described.

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First Claim