Polymer material

A polymer material comprising:

• a hydroxyl group-containing polymer which is acetalized with a compound represented by Formula (1),
• wherein the hydroxyl group-containing polymer contains two or more hydroxyl groups in a main chain and/or a side chain,
• the acetalization is based on a reaction between a group represented by —R2—CR1O in General Formula (1) and two hydroxyl groups in the hydroxyl group-containing polymer, and
• the polymer material forms a crosslinked substance by irradiation with light,
• wherein in the formula, R1 represents a hydrogen atom, a methyl group, or a cyclopropyl group, R2 represents a single bond, an alkylene group having 1 to 3 carbon atoms, an alkenylene group having 2 or 3 carbon atoms, or a group represented by —C(CR1O)—, R3 each independently represents an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group having 1 to 3 carbon atoms, a hydroxyl group, a halogen atom, an alkoxycarbonyl group, a nitro group, or an arylsulfonyl group, n represents an integer of 0 or 1 representing a monocycle or a fused ring, m represents the number of R3 bonded to an aromatic ring, m represents an integer of 0 to 4 in a case where n represents 0, and m represents an integer of 0 to 6 in a case where n represents 1, where the nitro group in the formula is adjacent to the group represented by —R2—CR1O or is adjacent to R3 which represents an alkyl group having 1 to 3 carbon atoms.