| abstract |
The present invention relates to compounds of formula (I) The compounds of formula I may be photochromic compounds. The present invention also relates to photochromic compositions and photochromic articles comprising, for example, at least one photochromic compound of formula (I). Formula I In this formula, Ring A is, for example, an aryl group; L < 1 > is a chiral or non-chiral extender. |