The present invention relates to a photo-curable polymer composition comprising: a) a first block copolymer comprising at least two blocks A of polymerised mono-vinyl aromatic monomer, and at least one block B of polymerised conjugated diene monomer, wherein the total polymerised mono-vinyl aromatic monomer content is in the range from 5 to 25% by weight of the block copolymer; b) 5 to 10% by weight of a second block copolymer having one block A of polymerised mono-vinyl aromatic monomer and at least one block B of polymerised conjugated diene monomer, wherein the total polymerised mono-vinyl aromatic monomer content is in the range from 5 to 50% by weight of the block copolymer, alkoxy or epoxy functional groups; and c) at least 5% by weight of a low molecular weight block copolymer, wherein the total of (b) and (c) is from 15% by weight to 80% by weight, the low molecular weight block copolymer having one block A of polymerised mono-vinyl aromatic monomer, and at least one block B of polymerised conjugated diene monomer, and having a weight average molecular weight in the range of from 1,000 to 35,000.