Azulene and derivatives thereof as colorants

Composition comprising a compound selected from siloxane, a perfluorocarbon compound, a perfluoroether, a perfluoroamine and mixtures thereof as a main component, based on the total weight of the composition, and azulene or an azulene derivative of the formula (II),

• wherein in formula (II) the groups R1 to R8 can be the same or different and are independently selected from a hydrogen atom, a halogen atom, a cyano group, a linear alkyl group, a group —(CH2)n-phenyl, a group —(CH2)n-pyridyl, a group —(CH2)n-thiophene, wherein n is an integer from 0 to 6, a naphthalene group, wherein one or two CH groups can be replaced with nitrogen atoms, or an anthracene group, wherein one or two CH groups can be replaced with nitrogen atoms,
• wherein the linear alkyl group is an alkyl group with at least one and at most 37 C-atoms, wherein one to 10 CH2 units can independently be replaced each with a carbonyl group, an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, a cis- or trans-CH═CH group, wherein one CH unit can also be replaced with a nitrogen atom, an acetylenic C≡C group, a divalent phenyl group, a divalent pyridine group, a divalent thiophene group, a divalent naphthalene group, wherein one or two CH groups can be replaced with nitrogen atoms, or a divalent anthracene group, wherein one or two CH groups can be replaced with nitrogen atoms,
• wherein up to 12 individual hydrogen atoms of the CH2 groups in an alkyl group can independently be replaced even on the same C-atom each with a halogen atom, a cyano group, or a linear alkyl chain with up to 18 C-atoms, wherein one to 6 CH2 units can independently be replaced each with a carbonyl group, an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, a cis- or trans-CH═CH group, wherein one CH unit can also be replaced with a nitrogen atom, an acetylenic C≡C group, a divalent phenyl group, a divalent pyridine group, a divalent thiophene group, a divalent naphthalene group, wherein one or two CH groups can be replaced with nitrogen atoms, or a divalent anthracene group, wherein one or two CH groups can be replaced with nitrogen atoms, and wherein up to 12 individual hydrogen atoms of the CH2 groups in the alkyl chain which can serve as the substituent at the alkyl group can independently be replaced also on the same carbon atom each with a halogen atom, a cyano group, or a linear alkyl chain with up to 18 C-atoms, wherein one to 6 CH2 units can independently be replaced with a carbonyl group, an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, a cis- or trans-CH═CH group, wherein one CH unit can also be replaced with a nitrogen atom, an acetylenic C≡C group, a divalent phenyl group, a divalent pyridine group, a divalent thiophene group, a divalent naphthalene group, wherein one or two CH groups can be replaced with nitrogen atoms, or a divalent anthracene group, wherein one or two CH groups can be replaced with nitrogen atoms,
• and wherein two linear alkyl groups as defined above and located at different positions R1 to R8 can optionally be linked to each other forming a ring;
• and
• wherein the azulene or azulene derivative of formula (II) is dissolved in the compound selected from a siloxane, a perfluorocarbon compound, a perfluoroether, a perfluoroamine and combinations thereof.