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Abstract

Described are photochromic 2H-naphtho[1,2-b]pyrans characterized by two adjacent moderate to strong electron donor substituents at the 7 and 8 positions, a moderate to strong electron withdrawing substituent at the 5 position, and at the 2 position, one substituent that is a weak electron donor and another substituent that is a weak to moderate electron donor. An optional substituent is located at the 6 position and each of the positions may have reactive substituents that enable the photochromic material to be more compatible with the host polymer. The selection and placement of the aforementioned substituents being done on the naphthopyran to demonstrate a lambda max of less than 490 nanometers in the Photochromic Performance Test. The selection and placement of substituents also enables the balancing of photochromic properties, such as the intensity, as measured in the Photochromic Performance Test. Also described are polymeric organic host materials that contain or that are coated with such naphthopyrans or combinations thereof with complementary photochromic compounds to produce photochromic articles such as ophthalmic lenses.

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