Polymer, coating composition comprising same, and organic light-emitting device using same

A polymer comprising a unit represented by the following Chemical Formula 1:

• wherein, in Chemical Formula 1,
• Ar1 to Ar5 are the same as or different from each other, and each independently a substituted or unsubstituted aryl group;
• Ar2 and Ar3 are optionally bond to each other to form a substituted or unsubstituted heteroring;
• Ar4 and Ar5 are optionally bond to each other to form a substituted or unsubstituted heteroring;
• L1 and L2 are the same as or different from each other, and each independently a direct bond;
• or a substituted or unsubstituted arylene group;
• Y is (Y2)i-Y3-;
• Y3 is a substituted or unsubstituted arylene group;
• or a substituted or unsubstituted alkylene group;
• each Y2 is independently a substituted or unsubstituted arylene group;
• a substituted or unsubstituted alkylene group;
• or —O—;
• i is an integer of 1 to 8, and when i is 2 or greater, Y2s are the same as or different from each other, and (Y2)i contains at least one —O—;
• R1 to R5 are the same as or different from each other, and each independently hydrogen, or a substituted or unsubstituted alkyl group;
• and
• l and k are the same as or different from each other, and each independently an integer of 0 to 3, and when 1 is 2 or greater, R1s are the same as or different from each other, and when k is 2 or greater, R2s are the same as or different from each other.