Studies on Durability and Polarization Properties of Poly(vinyl alcohol) Polarizing Films Prepared with Reactive Dichroic Dyes

Abstract

Three reactive dichroic dyes with 3,5-dichloro-2,4,6-triazine moiety were synthesized by reaction between dichroic dyes (such as congo red, direct black 22 or direct black 4) and cyanuric chloride. Poly(vinyl alcohol) (PVA) films were dyed with the obtained three reactive dichroic dyes. After 400% drawing of the PVA films, their optical properties were compared with an iodine-doped PVA film prepared in the same condition. Durability test was performed at 50 degrees C in 85% of relative humidity for 120 hrs. We found that compared with the iodine-doped PVA polarizing film, the relative durability of the PVA polarizing film dyed with the reactive dichroic dyes was greatly improved.