| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to efficiently produce a single crystal of high- quality photochromic material with good reproducibility by using a specific photochromic single crystal and further specifying the impurity concn. thereof to a specific value or below. SOLUTION: This optical function element consists of the photochromic single crystal of formula I or formula II which reacts chemically and reversibly between isomers according to photoirradiation and further, the impurity concn. of the photochromic single crystal is confined to <=0.5 vol.% (inclusive of 0) to reduce irreversible reaction. In the formulas, R<1> , R<4> denote alkyl group, R<2> , R<3> , R<5> , R<6> denote alkyl groups or hydrogen atoms. The alkyl groups include a methyl group, ethyl group, propyl group, butyl group, amyl group, hexyl group, octyl group, nonyl group, stearyl group, cyclohexyl group, etc. The optical function element applicable to an optical memory element, such as, for example, a near field memory and hologram memory, and an optical switch element may be obtd. by using such photochromic single crystal. |
