| abstract |
An optical recording medium is provided in which anrecording layer contains a salt-forming dye between an ionnof an azo metal complex of the following formula (I) and annion of a cyanine dye of the following formula (II), having ancomplex index of refraction in the wavelength region ofnrecording light and/or reading light whose imaginary part knis up to 0.20, or at least one of azo oxovanadium metalncomplexes having an azo compound of the following formulan(III) as a ligand and metal complexes having azo compoundsnof the following formulae (IV) and (V) as a ligand.nRecording and reading can be carried out at a conventionalnwavelength or a short wavelength of about 630-690 nm ornboth.n (A-N=N-B) m ยท M 1 n n A-N=N-B n n In formulae (I) and (III), A is an aromatic ring groupnhaving an active hydrogen-bearing group at a position nadjacent to the diazo group or a nitrogenous heteroaromaticnring group having an oxovanadium-coordinatable nitrogen atomnat a position adjacent to the carbon atom in the ringnattached to the diazo group, and B is an aromatic ring groupnhaving an active hydrogen-bearing group at a positionnadjacent to the diazo group. In formula (I), m is equal ton1 or 2, and M 1 is a center metal. n In formula (II), Q 1 and Q 2 each are a group of atomsnforming a 5-membered nitrogenous heterocyclic ring which maynhave a fused ring, L is a methine chain, R 1 and R 2 each arenan alkyl group. n In formulae (IV) and (V), X is an active hydrogen-bearingngroup, R 1 and R 2 each are an alkyl group, the totalnnumber of carbon atoms in R 1 and R 2 is from 2 to 8, R is annitro group, and n is equal to 0 or 1. |