Block copolymer containing a monomer carrying photoactive a photoisomerizable group, its use in an optical memory 3d.

The invention relates to a block copolymer comprising:. at least one block A having a Tg of between -55 ° C and 0 ° C, preferably between -40 ° C and -1 ° C. at least one block B comprising at least one photoactive monomer carrying a photoisomerizable chromophore. The photoactive monomer has the formula (I): g id = "ID2931827-4" he = "" wi = "" file = "" img-format = "tif" />> wherein:. X denotes H or CH 3; . G is -OC (= O) -, -C (= O) -O-, phenyl, substituted or unsubstituted, or -NR-C (= O) -, NR being linked to L and R being H or alkyl C1-C10; . L denotes a spacer group; . CR denotes a photoisomerizable chromophore. The block copolymer provides a 3D optical memory. The invention also relates to the 3D optical memory.