| abstract |
Dichroic dyes in the form of the free acids of the general formula I correspond, where n stands for the numbers 1 or 2, A an optionally substituted aryl or heterocyclic radical, R₁ and R₃ independently of one another hydrogen or SO₃H R₂ is hydrogen, NH₂, NH-acyl, N (H) -alkyl, NH-aryl, R₄ hydrogen, OH, OR, SO₃H, C1 or the rest -N = NA 'in the A 'is an optionally substituted aryl or heterocyclic radical, R is an aliphatic radical with up to 4 carbon atoms and R₅ OH, NH₂ X means C1, SO₃H or H. Light-polarizing films based on water-soluble, transparent, organic polymers, in particular polyvinyl alcohol (PVAL), which contain the new dichroic dyes. |