Optical recording media

An optical recording medium comprising a substrate and a recording layer formed thereon, in which the recording layer is irradiated with beam of energy to form thereon pits corresponding to given pieces of information and thereby record the pieces of information, said recording layer being a thin film consisting essentially of Te and additionally containing Cr, C and H and said substrate consisting of a cycloolefin random copolymer composition comprising:

• [A] a cycloolefin random copolymer composed of an ethylene unit and a cycloolefin unit derived from the following general formula [I] and having an intrinsic viscosity [72 ] of from 0.05 to 10 dl/g as measured at 135.degree. C. in decalin and a softening temperature (TMA) of not lower than 70.degree. C., and
• [B] a cycloolefin random copolymer composed of an ethylene unit and a cycloolefin unit derived from the following general formula [I] and having an intrinsic viscosity [.eta.] of from 0.05 to 5 dl/g as measured at 135.degree. C. in decalin and a softening temperature (TMA) of below 70.degree. C., in such a proportion that the ratio by weight of the component [A] to the component [B] is in the range of from 100/0.1 to 100/10, ##STR85## wherein n is 0 or a positive integer, R.sup.1 to R.sup.12 are the same or difference, and represent each hydrogen atom, a halogen atom or a hydrocarbon group, provided that R.sup.9 to R.sup.12, when taken together, may form a mono- or poly-cyclic hydrocarbon ring which may optionally have double bond or bonds, or R.sup.9 and R.sup.10 or R.sup.11 and R.sup.12, when taken together, may form an alkylidene group.

An optical recording medium of improved sensitivity comprising a substrate and a recording layer in which the recording layer has improved adhesion to the substrate and improved oxidation resistance and in which the recording layer is irradiated with a beam of energy to form thereon pits corresponding to given pieces of information and thereby record the pieces of information, said recording layer being a thin film consisting essentially of Te, Cr, C and H, wherein Cr is present in an amount of from 0.1 to 40 atom %, based on the total atoms present in the recording layer, C is present in an amount of less than 40 atom %, based on the total atoms present in the recording layer, and H is present in an amount of from 1 to 40 atom %, based on the total atoms present in the recording layer, and said substrate comprises a cycloolefin random copolymer composition comprising:

• [A] a cycloolefin random copolymer composed of an ethylene unit and a cycloolefin unit from a cycloolefin of the general formula (I) ##STR87## wherein n is 0 or a positive integer, R.sup.1 to R.sup.12 are the same or different and each represents a hydrogen atom, a halogen atom or a hydrocarbon group, provided that R.sup.9 to R.sup.12, when taken together, may form a mono- or poly-cyclic hydrocarbon ring which may optionally have a double bond or bonds, or R.sup.9 and R.sup.10 or R.sup.11 and R.sup.12, when taken together, may form an alkylidene group, and having an intrinsic viscosity [.eta.] of from 0.05 to 10 dl/g as measured at 135.degree. C. in decalin and a softening temperature (TMA) of not lower than 70.degree. C., and
• (B) a cycloolefin random copolymer composed of an ethylene unit and a cycloolefin unit from a cycloolefin of said general formula (I), and having an intrinsic viscosity [.eta.] of from 0.05 to 5 dl/g as measured at 135.degree. C. in decalin and a softening temperature (TMA) of below 70.degree. C., in such a proportion that the ratio by weight of the component (A) to the component (B) is in the range of from 100/0.1 to 100/10.