| abstract |
Azo compounds whose free acid forms are represented by the general formula (1) are extremely useful as the dichroic dye to be used in polarizing plates which are excellent in polarization performance and endurance and reduced in the color cross-talk within the visible light region or in polarizers for liquid crystal projectors made by using them; (1) wherein R1 is sulfo, carboxy, or lower alkoxy and R2 is sulfo, carboxy, lower alkyl, or lower alkoxy, with the proviso that a case wherein both R1 and R2 are each sulfo is excepted; R3 to R6 are each independently hydrogen, lower alkyl, or lower alkoxy; and R7 and R8 are each independently hydrogen, amino, hydroxy, sulfo, or carboxy. |