Dichroic azo dyestuff and the polarizing film making from the same

摘要

The present invention relates to a azo dyestuff compound of the following formula (I), of which the free acid is represented by the following formula: wherein R₁, R₂, R₃, R₄, and n are defined as in the specification. The azo dyestuff compound of formula (I) of the present invention is used for preparing polarizing film. The present invention also relates to a polarizing film comprising the azo dyestuff compound of formula (I), which has excellent degree of polarization.