Abstract: The invention relates to a crosslinkable material containing a polymer onto which chromophores are laterally grafted, characterized in that each chromophore is within a polymer unit which corresponds to the following formula (I): ##STR1## in which: X represents a part of the polymer chain,A is a group --NO.sub.2, --CN, --C(CN).dbd.C(CN).sub.2 or --SO.sub.2 R.sub.4, R.sub.4 being a C.sub.1 to C.sub.6 alkyl,D is a nitrogen, sulphur or oxygen atom,R.sub.1 is a hydrogen atom or a C.sub.1 to C.sub.6 alkyl if D is a nitrogen atom, or nothing if D is a sulphur or oxygen atom,R.sub.2 is a C.sub.1 to C.sub.6 aliphatic alkyl group,and E is a group chosen from --OH, --O--CO--(CH.sub.2).sub.n --COOH, --O--W, --O--CO--R.sub.3 O--W and --O--R.sub.3 --O--W, n being an integer between 2 and 6, W being a photodimerizable group and R.sub.3 being a C.sub.1 to C.sub.6 alkyl,and the said material additionally containing complementary anchoring functional groups capable of attaching themselves to E during the crosslinking.

Abstract: The invention relates to a crosslinkable material that is active in non-linear optics, containing a polymer which carries chromophores each included in a polymer unit of formula: ##STR1## in which: T is part of the polymer chain,A is an --NO.sub.2, --CN or --C(CN).dbd.C(CN).sub.2 group,R.sub.1 is a hydrogen atom or a methyl or ethyl group,R.sub.2 is a CH.sub.2, C.sub.2 H.sub.4, C.sub.3 H.sub.6 or C.sub.4 H.sub.8 group, and:either X=Y is an azo group, F being a hydrogen atom and G being a group --C(O)--O--W or a group --C(O)--O--(CH.sub.2).sub.n --O--W, n being an integer between 2 and 6 and W being a hydrogen atom or a dimerizable group,or X=Y is an azomethine group, one of the groups F and G being a group --O--W or --R.sub.3 --O--W, R.sub.3 being a group --O--C(O)--R.sub.4 -- or --O--R.sub.4 --, where R.sub.4 is a C.sub.1 to C.sub.6 alkyl, the other of the groups F and G being a hydrogen atom and W being a hydrogen atom or a dimerizable group.