| abstract |
PURPOSE:To enable rewriting in a photon mode, by providing a thermal recording layer comprising a copolymer of a (meth)acrylic acid-modified spiropyran compound with an oligoester (meth)acrylic acid compound on a base. CONSTITUTION:A copolymer of a (meth)acrylic acid-modified spiropyran compound of formula I (R1 is H or CH3, and n is an integer of 1-20) with an oligoester (meth)acrylic acid compound having a molecular weight of 150-2,000 and having at least two (meth)acryl groups at terminals of the molecule thereof, the polymer having a glass transition temperature Tg of at least 50 deg.C and an activation energy (DELTAHbeta) based on local relaxation of not more than 20kcal/ mol is synthesized. The copolymer is dissolved in an organic solvent to prepare a coating liquid, which is applied to a base, and is dried to provide a thermal recording layer, thereby obtaining a rewritable-type optical recording material. |