Abstract: Certain types of aryl nitrogen compounds are found to be useful not only for effectively rendering dyes lightfast but also for using as an additive that has high solubility in solvents and sufficiently good miscibility with dyes to insure that their solubility will not be impaired. They can be used for preventing various reactions that cause deterioration by light in organic dyes, in particular cyanine dyes. They can also be used for improving the keeping quality and recording and reproduction characteristics of optical recording media that use organic dyes in the form of thin films. Representative examples include N, N-lower alkyl substituted nitrosoanilines, phenol or naphthol derivatives having at least one nitroso group, nitrosodiphenylamine and its derivatives and 1-pycryl-2, 2-diarylhydrazyl free radicals.

Abstract: An optical information recording medium comprising a light transmitting substrate having a spiral pregroove formed on its surface, a light absorptive layer of a coloring matter formed on the substrate directly or with other layer interposed therebetween, and a light reflective layer made of a metal film formed on the light absorptive layer directly or with other layer interposed therebetween, wherein .DELTA.S.ltoreq.0.3 wherein .DELTA.S is the optical phase difference represented by .DELTA.S=2d.sub.sub {n.sub.sub -n.sub.abs (1-d.sub.abs /d.sub.sub)}/.lambda. wherein d.sub.sub is the depth of the layer boundary on the substrate side of the light absorptive layer at the portion corresponding to the pregroove, d.sub.abs is the depth of the layer boundary on the light absorptive layer side of the light reflective layer at the portion corresponding to the pregroove, n.sub.