Medium comprising, one or more liquid-crystalline compounds, one or more dichroic dyes, and one or more compounds having a three-dimensional structure, a molecular weight of greater than 450 Da, and one or more anchor groups, whereby compound is selected from the group of silsesquioxane compounds or one or more organic compounds having one or more ring groups, and one or more anchor groups, whereby compound is selected from the group of compounds of formula B-I, R B1 -A B1 -(Z B1 -A B2) m -R B2 B-I, wherein, A B1 and A B2 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which may also be mono- or polysubstituted by a group L, L in each case, independently of one another, denotes OH, (CH 2) n -OH, F, Cl, Br, I, CN, -NO 2, -NCO, -NCS, OCN, SCN, -C(=O)N(R 0) 2, C(=O)R 0, -N(R 0) 2, -(CH 2) n -N(R 0) 2, optionally substituted silyl, optionally substituted aryl or cycloalkyl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl, Z B1 in each case, independently of one another, denotes -O-, S, -CO-, CO-O-, OCO-, -O-CO-O-, OCH 2 -, CH 2 O-, SCH 2, -CH 2 S-, CF 2 O-, OCF 2 -, CF 2 S-, -SCF 2 -, (CH 2) n -, CF 2 CH 2 -, CH 2 CF 2 -, (CF 2) n -, CH=CH-, CF=CF-, C=C-, CH=CH-COO-, OCO-CH=CH-, CR 0 R 00 or a single bond, R 0 and R 00 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, R B1 denotes H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may be replaced by -NR 0 -, -O-,-S-, -CO-, CO-O-, -O-CO-, -O-CO-O- in such a way that N, O and/or S atoms are not linked directly to one another, and in which, in addition, one or more tertiary carbon atoms (CH groups) may be replaced by N, and in which, in roup of silsesquioxane compounds R B2 denotes, a straight-chain, branched or cyclic alkyl group or aryl group having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may be replaced by -NR 0 -, -O-, -S-, -CO-, CO-O-, -O-CO-, -O-CO-O- in such a way that N, O and/or S atoms are not linked directly to one another, and in which, in addition, one or more tertiary carbon atoms (CH groups) may be replaced by N, and in which, in addition, one or more H atoms may be replaced by F or Cl, with the proviso that the radical R B2 contains one or more heteroatoms selected from N, S and/or O, m denotes 0, 1, 2, 3, 4 or 5, and n denotes 1, 2, 3 or 4. A B1 and A B2 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which may also be mono- or polysubstituted by a group L, L in each case, independently of one another, denotes OH, (CH 2) n -OH, F, Cl, Br, I, CN, -NO 2, -NCO, -NCS, OCN, SCN, -C(=O)N(R 0) 2, C(=O)R 0, -N(R 0) 2, -(CH 2) n -N(R 0) 2, optionally substituted silyl, optionally substituted aryl or cycloalkyl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl, Z B1 in each case, independently of one another, denotes -O-, S, -CO-, CO-O-, OCO-, -O-CO-O-, OCH 2 -, CH 2 O-, SCH 2, -CH 2 S-, CF 2 O-, OCF 2 -, CF 2 S-, -SCF 2 -, (CH 2) n -, CF 2 CH 2 -, CH 2 CF 2 -, (CF 2) n -, CH=CH-, CF=CF-, C=C-, CH=CH-COO-, OCO-CH=CH-, CR 0 R 00 or a single bond, R 0 and R 00 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, R B1 denotes H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may be replaced by -NR 0 -, -O-,-S-, -CO-, CO-O-, -O-CO-, -O-CO-O- in such a way that N, O and/or S atoms are not linked directly to one another, and in which, in addition, one or more tertiary carbon atoms (CH groups) may be replaced by N, and in which, in roup of silsesquioxane compounds R B2 denotes, a straight-chain, branched or cyclic alkyl group or aryl group having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may be replaced by -NR 0 -, -O-, -S-, -CO-, CO-O-, -O-CO-, -O-CO-O- in such a way that N, O and/or S atoms are not linked directly to one another, and in which, in addition, one or more tertiary carbon atoms (CH groups) may be replaced by N, and in which, in addition, one or more H atoms may be replaced by F or Cl, with the proviso that the radical R B2 contains one or more heteroatoms selected from N, S and/or O, m denotes 0, 1, 2, 3, 4 or 5, and n denotes 1, 2, 3 or 4.