| 摘要 |
PURPOSE:To effectively record and hold information at the time of repeated reproduction by superposing a recording layer of photochromic compound and a protective layer of a polyvinyl alcohol on a board. CONSTITUTION:Spiropyran compound of photochromic compound produces a structural charge when isomerizing to merocyanine type of optically colored state, and the life of the exciting triplet state of a reactive intermediate is affected by the influence of the responding speed of the colored state. Then, in order to suppress the reaction of the exciting triplet state with O2, a recording layer is covered with PVA having small O3 permeability as a protective layer to prolong the life of optical absorption isomerization in the exciting triplet state, and the repeated stability of recording and reproducing can be improved. In the case of the recording medium using a photochromic material recording layer combined with the spiropyran compound and polymer binder such as polycarbonate, the recording layer is provided with the protective layer of the PVA in this mummer or the PVA is used as the binder, thereby effectively holding information recording even in the repeated reproduction. |
