| 摘要 |
PURPOSE:A photochromic substance, consisting of a specific naphthoxazine derivative having (partial) water-solubility and applied to fields of sunglasses, optical filters, curtains, etc. CONSTITUTION:A photochromic substance consisting of a spironaphthoxazine derivative expressed by the formula [one of X1 and X2 is carboxylic acid (alkali metal salt) or 1-6C alkyl ester of carboxylic acid, and the other is H; X3 and X4 are H, 1-3C alkyl, 1-3C alkoxy, halogen or cyano; R is 1-30C straight chain alkyl].
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