| abstract |
The present invention provides a photochromic material which is an indeno-fused naphthopyran having a pi-conjugation extending group bonded to the 11-position of the indeno-fused naphthopyran, the pi-conjugation extending group having at least one pendent halo-substituted group bonded thereto. The pi-conjugation extending group extends the pi-conjugation system of said indeno-fused naphthopyran. The 13-position of the indeno-fused naphthopyran is substantially free of spiro-substituents. The invention further provides photochromic materials of specified structure, photochromic compositions, photochromic articles and optical elements that include the photochromic material. |