Rhodamine-based coloring composition

A polymer having a monomer unit derived from the compound represented by the following general formula (1):

• wherein R1 to R4 each independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, a sulfoalkyl group having 1 to 6 carbon atoms, a carboxyalkyl group having 2 to 7 carbon atoms, a cyanoalkyl group having 2 to 7 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, a phenyl group having a substituent or not having a substituent, or a benzyl group having a substituent or not having a substituent;
• R7 represents a hydrogen atom or a methyl group;
• An−represents an anion containing an aryl group having an electron-withdrawing substituent, a sulfonyl group having an electron-withdrawing substituent, or a halogenated alkyl group;
• A1 represents an alkylene group having 1 to 6 carbon atoms which has at least one group selected from —OCO—, —COO— and —NHCONH—in the chain;
• or an alkylene group having 1 to 6 carbon atoms;
• and
• (a) when A1 represents the alkylene group having 1 to 6 carbon atoms which has at least one group selected from —OCO—, —COO— and —NHCONH— in the chain, A2 represents —NH— or —O—;
• Y represents a nitrogen atom or the group represented by the following formula (1-1):
• n represents an integer of 0 to 3:
• R9 represents a hydrogen atom;
• and R9 represents a hydrogen atom;
• and
• (b) when A1 represents the alkylene group having 1 to 6 carbon atoms, A2 represents —NH— or —O— ;
• Y represents a nitrogen atom or the group represented by the above formula (1-1);
• n represents 2;
• R8 and R9 form the following cyclic structure of a 6 membered ring
• together with —N—(CH2)n—Y— bonding thereto.