Photochromic material and an optical storage medium using the same

摘要

The present invention provides a photochromic material which comprises a spiropyran compound of formula (I): (I) wherein R1 and R2 are independently alkyl groups each containing 1 to 30 carbon atoms and Y is a halogen. The photochromic material possesses absorption sensitivity at wavelengths in the length region of about 700 nm which is the oscillation range of a semi-conductor laser device, and possesses higher stability compared with conventional one when it becomes a colored form.