Patent ID: 8652364

Claim:
A polymer film comprising at least one compound represented by formula (I): wherein A 1 and A 2 each independently represent a group having a Hammett's σp value of 0.2 or more, or bond each other to form a cyclic active methylene structure; and X 1 and X 2 each independently represent a hydrogen atom, aryl group, hetero-cyclic group, cyano, N-alkyl- or N-aryl-carbamoyl, or alkyl- or aryl-oxycarbonyl, or bond each other to form a saturated ring in which nitrogen and carbon atoms are embedded, and the group and ring may have at least one substituent, provided that: when both of X 1 and X 2 are cyano, then A 1 and A 2 each represents cyano, and when both of X 1 and X 2 are not cyano, then A 1 and A 2 are bonded to each other to form a ring selected from the following structures, wherein “*” indicates a portion linking to formula (I), and R 0 and R 1 each independently represents a hydrogen atom or an alkyl or phenyl group which may have at least one substituent, or bond to each other to form a ring: