Fluorine-containing copolymer, composition for forming film, and optical film

A fluorine-containing copolymer comprising:

• a repeating unit represented by General Formula (I);
• and a repeating unit represented by General Formula (II),
• in General Formula (I), R1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, L1 represents a divalent linking group including at least one selected from the group consisting of —O—, —(C═O)O—, —O(C═O)—, —(C═O)—NH—, —NH—(C═O)—, a divalent aromatic group, or a divalent alicyclic group, L2 represents a single bond or a divalent linking group, and X is represented by General Formula (III) or General Formula (IV),
• in General Formulae (III) and (IV), * represents a bonding site to L2 in General Formula (I),
• in General Formula (II), R2 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, L3 represents a divalent linking group including at least one selected from the group consisting of —O—, —(C═O)O—, —O(C═O)—, —(C═O)—NH—, —NH—(C═O)—, a divalent aromatic group, or a divalent alicyclic group, L4 represents a single bond, an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 1 to 20 carbon atoms, a divalent aromatic group, —O—, —(C═O)O—, —O(C═O)—, —(C═O)—NH—, —NH—(C═O)—, or a divalent linking group consisting of a combination of the above-described bond or groups;
• however, L4 does not represent a linking group including —O(C═O)—NH—, and Y is an acryloyloxy group, a methacryloyloxy group, or an acryloylamino group,
• wherein a weight average molecular weight is 1,000 to 100,000.