| 摘要 |
A novel photochromic compound which develops a color of a neutral tint and has high color optical density, high fading speed and excellent durability. The present invention is a chromene compound having an indeno(2,1-f)naphtho(1,2-b)pyran structure as the basic skeleton in which a hetero ring having two hetero atoms including at least one sulfur atom is directly bonded to the 6-position and the 7-position of the indeno(2,1-f)naphtho(1,2-b)pyran structure via the hetero atom like the compound represented by the following formula (18). |
