Copolymer including ultraviolet light-absorbing group and compositions including the same

A copolymer comprising:

• first divalent units independently represented by formula:
• wherein
• X is a bond, alkylene, or alkyleneoxy, wherein the alkylene or alkyleneoxy have from 1 to 10 carbon atoms and are optionally interrupted by one or more —O— groups and optionally substituted by a hydroxyl group;
• R is alkyl having from one to four carbon atoms;
• n is 0 or 1;
• and
• Z is a 4,6-bisphenyl[1,3,5]triazin-2-yl group wherein each phenyl is optionally independently substituted by one or more alkyl or alkoxy groups;
• second divalent units represented by formula:
• and
• third divalent units represented by formula:
• wherein
• each R1 is independently hydrogen or methyl;
• R2 is a straight-chain or branched alkyl having from 1 to 20 carbon atoms;
• each V is independently O or NH;
• W is alkylene having from 1 to 10 carbon atoms;
• and
• each R′ is independently alkyl having from 1 to 6 carbon atoms.