| 摘要 |
The present invention relates to photochromic benzopyrans and to the use thereof in plastics of all kinds, especially for ophthalmic purposes. The inventive compounds are photochromic benzopyran compounds in which a polycyclic aromatic is joined to the 5 and 6 positions of a benzopyran, where the bond in the 6 position is direct and the bond in the 5 position is via a mono- or diatomic bridge.
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