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: Fluorescent dyes having the formula ##STR1## wherein R.sup.1 represents hydrogen, (C.sub.1 -C.sub.8) alkyl, trifluoromethyl, (C.sub.1 -C.sub.4) alkoxycarbonyl, (C.sub.1 -C.sub.4) alkoxycarbonyl (C.sub.1 -C.sub.4) alkyl, phenyl, or aralkyl group; R.sup.2 represents hydrogen, cyano, acyl, (C.sub.1 -C.sub.8) alkoxycarbonyl, (C.sub.1 -C.sub.4) alkoxy (C.sub.1 -C.sub.4) alkoxycarbonyl, (C.sub.1 -C.sub.4) alkoxy (C.sub.1 -C.sub.4) alkoxy (C.sub.1 -C.sub.4) alkoxycarbonyl, di(C.sub.1 -C.sub.4) alkylamino (C.sub.1 -C.sub.4) alkoxycarbonyl, cyclohexyloxycarbonyl, aryloxycarbonyl, benzyloxycarbonyl, tetrahydrofurfuryloxycarbonyl, carbamoyl, N-(C.sub.1 -C.sub.4) alkylcarbamoyl, N,N-di(C.sub.1 -C.sub.4)alkylcarbamoyl, N-phenylcarbamoyl, or morpholinocarbonyl group; and R.sup.3 and R.sup.4 can be the same or different and each represents hydrogen, (C.sub.1 -C.sub.8) alkyl, (C.sub.1 -C.sub.4) alkoxy(C.sub.1 -C.sub.4) alkyl, aralkyl or phenyl group which can be substituted by halogen atoms, (C.sub.1 -C.sub.