ASYMMETRICAL TRIMETHINE CYANINE DYE FOR HIGH CAPACITY OPTICAL RECORDING MEDIUM

PROBLEM TO BE SOLVED: To provide an optical recording material having an asymmetrical trimethine cyanine structure and provide an optical recording medium having a storage capacity of not less than 3 GB by using the optical recording material. SOLUTION: The optical recording material is an asymmetrical trimethine cyanine dye having a structure as represented by formula I (wherein R1 is H, a methyl group or an ethyl group; R2 and R3 are each independently a 1-12C substituted or unsubstituted alkyl group; A- is a halogen atom, ClO4- or the like; X is H, an alkyl group, an alkoxy group, a halogen atom, a nitro group or a condensed benzene group; and Y is H, an alkoxy group, a halogen atom, an alkyl group, an aryl group, an alkoxycarbonyl group, an aryloxycarbonyl group or the like). The material has a maximum absorption wavelength of 550-590 nm and a mole absorptivity of not less than 1×105 cm-1mol-1 litter. The trimethine cyanine dye is eminently suitable for use as a recording material for a high density optical recording medium, especially for a high density optical recording medium using a laser beam with a wavelength of 620-660 nm.