| abstract |
The present invention relates to photochromic 2H-naphtho[1,2-b]pyrans as well as their use in synthetic resins of all types, especially for ophthalmic purposes. In particular, the present invention relates to photochromic naphthopyran compounds, for which a further ring system is bonded to the f side of the naphthopyran. The inventive photochromic dyes generally have the general formula (I)wherein n, R1, R2, R3, X, B and B' are defined as in claim 1. The inventive compounds are distinguished by good darkening and decolorizing properties and a very good service life. |