Abstract: A method of optically writing an information over an information recorded on a recording material which is reversively convertible between a stable phase and a metastable phase to show different light reflection or transmission by controlling a heating condition to be applied to the recording material wherein the recorded information is recorded in the form of a plurality of separated metastable-phase areas on a stable-phase area is disclosed.

Abstract: A novel information recording medium comprising a substrate and a recording layer for writing information by means of laser beam which is provided on the substrate is disclosed. The recording layer contains an organic metal complex compound and a sensitizing agent for laser beam. Alternatively, the recording layer contains an organic metal complex compound and this recording layer is arranged in contact with a layer of a sensitizing agent for laser beam.

Abstract: An information recording medium including a substrate, an optional intermediate layer arranged on the substrate, and a recording layer arranged on the intermediate layer on the substrate, the recording layer including a low melting metal selected from the group consisting of In, Te, Sn, Pb and Bi and a metal compound selected from a metal sulfide, a metal fluoride and a metal oxide. The recording layer further contains a metal having a high surface tension of not less than 600 dyne/cm within temperatures from its melting point to a temperature higher than the melting point by 300.degree. C., the concentrations of the metal varying along the depth direction of the recording layer in such manner that the concentration of the metal on the side facing the substrate is higher than that of the metal on the opposite side where the metal on the side facing the substrate may be in the form of islands.

Abstract: Improvement in an information recording medium comprising two disc-shaped substrates, said two substrates being combined with each other directly or via ring-shaped spacers by an adhesive, and a recording layer for writing or reading information with laser beam which is provided on the inner surface of at least one substrate, wherein a layer of chlorinated polyolefin is provided between the substrate and the recording layer and further on the area where the substrate is combined with another substrate or the spacers, and said adhesive is a UV-curable epoxy adhesive which is arranged on the chlorinated polyolefin layer, optionally, via a primer layer.