A polymer comprising: a first unit represented by the following Formula 1; and a second unit represented by the following Formula 2: in Formulae 1 and 2, X is a curing group, L1. is -O-; a substituted or unsubstituted alkylene group; a substituted or unsubstituted arylene group; a substituted or unsubstituted divalent amine group; or a substituted or unsubstituted heteroarylene group; L2 to L5 are the same as or different from each other, and are each independently a direct bond; -O-; a substituted or unsubstituted alkylene group; a substituted or unsubstituted arylene group; a substituted or unsubstituted divalent amine group; or a substituted or unsubstituted heteroarylene group, b1 and b2 are each an integer from 1 to 10, when b1 and b2 are each 2 or more, two or more L1s and L5s are each the same as or different from each other, Ar1 and Ar2 are the same as or different from each other, and are each independently a substituted or unsubstituted aryl group, R1 to R9 are the same as or different from each other, and are each independently hydrogen; deuterium; a halogen group; a hydroxyl group; a nitrile group; a substituted or unsubstituted alkyl group; a substituted or unsubstituted cycloalkyl group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted heterocyclic group, r4 is an integer from 1 to 5, r5 is an integer from 1 to 4, r6 is an integer from 1 to 3, when r4 to r6 are each 2 or more, two or more R4s to R6s are each the same as or different from each other, m1 is a mole fraction and 0 < m1 < 1, m2 is a mole fraction and 0 < m2 < 1, and m1 + m2 ≤ 1. a first unit represented by the following Formula 1; and a second unit represented by the following Formula 2: in Formulae 1 and 2, X is a curing group, L1. is -O-; a substituted or unsubstituted alkylene group; a substituted or unsubstituted arylene group; a substituted or unsubstituted divalent amine group; or a substituted or unsubstituted heteroarylene group; L2 to L5 are the same as or different from each other, and are each independently a direct bond; -O-; a substituted or unsubstituted alkylene group; a substituted or unsubstituted arylene group; a substituted or unsubstituted divalent amine group; or a substituted or unsubstituted heteroarylene group, b1 and b2 are each an integer from 1 to 10, when b1 and b2 are each 2 or more, two or more L1s and L5s are each the same as or different from each other, Ar1 and Ar2 are the same as or different from each other, and are each independently a substituted or unsubstituted aryl group, R1 to R9 are the same as or different from each other, and are each independently hydrogen; deuterium; a halogen group; a hydroxyl group; a nitrile group; a substituted or unsubstituted alkyl group; a substituted or unsubstituted cycloalkyl group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted heterocyclic group, r4 is an integer from 1 to 5, r5 is an integer from 1 to 4, r6 is an integer from 1 to 3, when r4 to r6 are each 2 or more, two or more R4s to R6s are each the same as or different from each other, m1 is a mole fraction and 0 < m1 < 1, m2 is a mole fraction and 0 < m2 < 1, and m1 + m2 ≤ 1. X is a curing group, L1. is -O-; a substituted or unsubstituted alkylene group; a substituted or unsubstituted arylene group; a substituted or unsubstituted divalent amine group; or a substituted or unsubstituted heteroarylene group; L2 to L5 are the same as or different from each other, and are each independently a direct bond; -O-; a substituted or unsubstituted alkylene group; a substituted or unsubstituted arylene group; a substituted or unsubstituted divalent amine group; or a substituted or unsubstituted heteroarylene group, b1 and b2 are each an integer from 1 to 10, when b1 and b2 are each 2 or more, two or more L1s and L5s are each the same as or different from each other, Ar1 and Ar2 are the same as or different from each other, and are each independently a substituted or unsubstituted aryl group, R1 to R9 are the same as or different from each other, and are each independently hydrogen; deuterium; a halogen group; a hydroxyl group; a nitrile group; a substituted or unsubstituted alkyl group; a substituted or unsubstituted cycloalkyl group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted heterocyclic group, r4 is an integer from 1 to 5, r5 is an integer from 1 to 4, r6 is an integer from 1 to 3, when r4 to r6 are each 2 or more, two or more R4s to R6s are each the same as or different from each other, m1 is a mole fraction and 0 < m1 < 1, m2 is a mole fraction and 0 < m2 < 1, and m1 + m2 ≤ 1.