| 摘要 |
PURPOSE:To enable optical signals to be stably written and reproduced and enhance stability to reproducing light, sunlight and moisture, by providing a recording layer comprising a specified organic coloring matter, in an optical memory medium for writing and reproducing information by semiconductor laser. CONSTITUTION:A recording layer comprising an organic coloring matter of formula I is provided. The organic coloring matter has a halogen introduced as Z to the benzene ring constituting the indole, whereby the electron density on the N atom is lowered, and reproduction deterioration characteristics and light resistance (which is one factor of preservability) can be improved. In formula I, R1 is a 1-6C alkyl or phenyl, and A1 is formula II, wherein R2 is hydrogen atom, a halogen atom, 1-8C alkyl, phenyl, diphenylamino or aralkyl. |
