Abstract: An information recording medium is disclosed, comprising a substrate having provided thereon a recording layer capable of recording information by a laser ray, wherein the recording layer contains a dye compound represented by formula (I-1): wherein R1, R2, R3 and R4 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted heterocyclic group, L1, L2 and L3 each independently represents a methine group which may have a substituent, m represents 0, 1, 2 or 3, Xk+ represents a cation and k represents an integer of from 1 to 10, provided that when m is 2 or 3, the plurality of L2 and L3 groups may be the same or different. Also disclosed is an information recording method using the above-described information recording medium.

Abstract: An optical information recording medium provided on a substrate thereof with a recording layer comprising a dye-containing layer, wherein the recording layer further comprises an organometallic dye compound containing a metal or a metallic ion, which is characterized in that an absorption spectrum curve of the recording organic dye is intersected with an absorption spectrum curve of the organometallic dye compound, and that the organometallic dye compound exhibits a maximum absorption wavelength on a longer wavelength side in relative to a maximum absorption wavelength of the recording organic dye.

Abstract: An optical recording medium comprising a transparent substrate and at least a recording layer containing an organic dye, a reflecting metal layer and a protective layer sequentially laminated on the substrate in this order, which has the following characteristics (a) to (c): (a) the substrate has a tracking groove with a track pitch of from 0.7 to 1.0 &mgr;m and the recording layer shows a modulation amplitude of EFM signal of at least 50% when recording is carried out by a laser beam with a wavelength of from 600 to 700 nm, and has a reflectance of from 45 to 65%; (b) in a thermogravimetric analysis of the dye, the inclination of the weight reduction to the temperature in the main weight reduction process is at least 2%/°C.; and (c) in the thermogravimetric analysis of the dye, the total weight reduction in the main weight reduction process is at least 25%.

Abstract: A novel aminium compound exhibiting excellent solubility for solvents and high safety in terms of handling and environment is provided. An aminium compound represented by the following formula (1): wherein R1 represents substituted or unsubstituted alkyl and A2− represents a divalent organic anion.

Abstract: An optical recording medium has deposited on a substrate a recording layer incorporating therein a cyanine dye, preferably an indoline dye, and optionally incorporating therein an autoxidizable compound or a thermoplastic resin and/or a singlet oxygen quencher.

Abstract: An optical recording medium is provided in which a recording layer contains a salt-forming dye between an ion of an azo metal complex of the following formula (I) and an ion of a cyanine dye of the following formula (II), having a complex index of refraction in the wavelength region of recording light and/or reading light whose imaginary part k is up to 0.20, or at least one of azo oxovanadium metal complexes having an azo compound of the following formula (III) as a ligand and metal complexes having azo compounds of the following formulae (IV) and (V) as a ligand. Recording and reading can be carried out at a conventional wavelength or a short wavelength of about 630-690 nm or both.