| abstract |
Described are novel reversible photochromic spiro(indoline) naphthoxazine compounds of improved photocolorability that may be graphically represented by the formula, <IMAGE> I In preferred embodiments, R1 is allyl, alkoxyalkyl, and alkyl; each R2 is alkyl or alkoxy; R3 and R4 are alkyl; R5 is alkoxycarbonyl; and R6 is hydroxy, alkoxy, or carboxy, e.g., acetoxy. 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 naphthoxazine compounds or combination thereof with complementary photochromic compounds, e.g., naphthopyran or benzopyran compounds, are also described. |