Abstract: A branched polycarbonate having a branching derived from a polyfunctional compound, comprising a repeating unit represented by general formula (1), a branched structure (a) derived from the polyfunctional compound and a branched structure (b) including at least one selected from the group consisting of branched structures represented by general formulas (2), (3) and (4), the total content of (a) and (b) with respect to (1) being 0.2-1.0 mol %, the ratio of (b) with respect to the total of (a) and (b) being 0.1-0.6, and the ratio of (2) with respect to the content of (b) being 0.5 or greater. [In formulas, Ar represents a divalent aromatic residue and Ar? represents a trivalent aromatic residue.

Abstract: A branched polycarbonate having a branching derived from a polyfunctional compound, comprising a repeating unit represented by general formula (1), a branched structure (a) derived from the polyfunctional compound and a branched structure (b) including at least one selected from the group consisting of branched structures represented by general formulas (2), (3) and (4), the total content of (a) and (b) with respect to (1) being 0.2-1.0 mol %, the ratio of (b) with respect to the total of (a) and (b) being 0.1-0.6, and the ratio of (2) with respect to the content of (b) being 0.5 or greater. [In formulas, Ar represents a divalent aromatic residue and Ar? represents a trivalent aromatic residue.

Abstract: Disclosed is a polycarbonate resin composition for the production of a substrate for an optical information medium, comprising 100 parts by weight of a polycarbonate resin, and 0.0005 to 1.0 part by weight of a mold release agent, wherein the composition exhibits a relative viscosity (&eegr;r) within the range of from 1.17 to 1.19, the relative viscosity (&eegr;r) being defined as the ratio (&eegr;/&eegr;o) of viscosity value (&eegr;) (25° C.) of a methylene chloride solution of the composition (concentration: 0.005 g/cm3) to viscosity value (&eegr;o) (25° C.) of methylene chloride, and wherein the relative viscosity (&eegr;r) of the composition and a melt index (MI) (JIS K 7210, at 280° C., under a load of 2.16 kg) of the composition satisfy the following formulae (I) and (II): &eegr;r≧−0.0723 log MI+1.316  (I) and &eegr;r≦−0.0723 log MI+1.324  (II).

Abstract: Disclosed is a polycarbonate resin composition for the production of a substrate for an optical information medium, comprising 100 parts by weight of a polycarbonate resin, and 0.0005 to 1.0 part by weight of a mold release agent, wherein the composition exhibits a relative viscosity (&eegr;r) within the range of from 1.17 to 1.19, the relative viscosity (&eegr;r) being defined as the ratio (&eegr;/&eegr;o) of viscosity value (&eegr;) (25° C.) of a methylene chloride solution of the composition (concentration: 0.005 g/cm3) to viscosity value (&eegr;o) (25° C.) of methylene chloride, and wherein the relative viscosity (&eegr;r) of the composition and a melt index (MI) (JIS K 7210, at 280° C., under a load of 2.