| 摘要 |
PCT No. PCT/US96/12083 Sec. 371 Date Jan. 28, 1998 Sec. 102(e) Date Jan. 28, 1998 PCT Filed Jul. 22, 1996 PCT Pub. No. WO97/08573 PCT Pub. Date Mar. 6, 1997The invention concerns photochromic compounds having a formula (I), where R1 is a polycyclo group formed by at least one alicyclic group linked to, bridged or condensed, with at least one other aliphatic or aromatic ring.
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