| abstract |
Various photochromic materials are provided that are essentially free of polymerizable unsaturated groups, and comprise: a) an indeno[2′,3′:3,4]naphtho[1,2-b]pyran; and b) an electron-withdrawing, non-conjugating group bonded at the 11-position of the indeno[2′,3′:3,4]naphtho[1,2-b]pyran. Alternative embodiments include various substituents at other positions of the indeno[2′,3′:3,4]naphtho[1,2-b]pyran. Also provided are photochromic articles including a substrate and one of the above photochromic materials, in contact with at least a portion of the substrate. |