| 摘要 |
<p>A chromene compound which comprises a skeleton represented by formula (1), shows a high color density and double peak properties under light irradiation, enables reduced initial coloration and has practically usable fading speed and durability. In formula (1), R1 represents an electron-donating group having a Hammett's constant less than 0; the ring containing X is a heterocycle formed by X together with the carbon atoms at the 7- and 8-positions; and X represents an oxygen atom, a sulfur atom or a group represented by =NR2 that is directly bonded to the carbon atom at the 7-position.</p> |
