Transparent heat-resistant resin optical material and film

An optical compensating film, comprising:

• a copolymer consisting essentially of an olefin residue unit represented by the following formula (i):
• wherein R1, R2, and R3 each represents hydrogen or an alkyl group having from 1 to 6 carbon atoms, and
• an N-phenyl-substituted maleimide residue unit represented by the following formula (ii):
• wherein
• R4 and R5 each represents hydrogen or a linear or branched alkyl group having from 1 to 8 carbon atoms;
• R7, R8, and R9 each represents hydrogen, a halogen based element, a carboxylic acid, a carboxylic acid ester, a hydroxyl group, a cyano group, a nitro group, or a linear or branched alkyl group having from 1 to 8 carbon atoms;
• and
• R6 and R10 each represents hydrogen, a halogen based element, a carboxylic acid, a carboxylic acid ester, a hydroxyl group, a cyano group, a nitro group, or a linear or branched alkyl group having from 1 to 8 carbon atoms, and
• when at least one of R6 or R10 represents hydrogen, the other should not be hydrogen but represent a halogen based element, a carboxylic acid, a carboxylic acid ester, a hydroxyl group, a cyano group, a nitro group, or a linear or branched alkyl group having from 1 to 8 carbon atoms,
• the copolymer having a weight average molecular weight, as reduced into standard polystyrene, of from 5×103 to 5×106,
• the optical compensating film being obtained by uniaxially stretch molding the copolymer,
• the optical compensating film having a relationship of three-dimensional refractive indexes of nz≧ny>nx in the case where the stretching direction is an x-axis within the film plane, the perpendicular direction to the x-axis within the film plane is a y-axis, and the vertical direction outside the film plane is a z-axis, nx stands for a refractive index in the x-axis direction, ny stands for a refractive index in the y-axis direction, and nz stands for a refractive index in the z-axis direction, and
• the optical compensating film exhibiting negative birefringence.