PURPOSE: To provide the title medium having high sensitivity, enhanced in the durability of a recording layer and performing the writing and reading of information by laser beam, obtained by successively providing an alkali diffusion preventing layer and a heat insulating layer between a glass substrate and the recording layer.
CONSTITUTION: The objective medium is obtained by successively providing a layer 2 for preventing the diffusion of the alkali metal ion and/or alkaline earth metal ion liberated from a glass substrate 1, a heat insulating layer 3 and a recording layer 4 capable of writing and/or reading information by laser to the glass substrate 1. The aforementioned medium is pref. prepared by successively providing the layer 2 comprising a styrene/maleic anhydride copolymer, the layer 3 comprising polymethylemetacrylate and/or nitrocellulose and the layer 3 comprising a mixture consisting of indium and germanium sulfide.
COPYRIGHT: (C)1986,JPO&Japio