Abstract: A process for preparing an iodine stainable polyester polarizer film which comprises:(a) extruding a moving molten web of polyester film; and(b) quenching said moving web to solidify it in a substantially amorphous form; and(c) applying an anchor coating to at least a portion of the surface of said film wherein said anchor coating improves adhesion of polyvinyl alcohol to polyester film; and(d) applying a coating of a dispersed aqueous composition of polyvinyl alcohol to at least a portion of the surface of said film; and(e) stretching said moving web in a direction transverse to the direction of motion while heating said web at a temperature of from about its glass transition temperature to about 160.degree. C.; and(f) crystallizing said moving web by heating it to a temperature in the range of 130.degree. C. to 240.degree. C. without stretching said web; and(g) cooling said web to substantially ambient atmospheric temperature.

Abstract: A polarizer having increased hydrolytic stability is produced by impregnating a polyvinyl alcohol substrate with an iodine containing composition and then subjecting the substrate to both concentrated infrared and ultraviolet radiation treatments sufficient to substantially increase the hydrolytic stability of the thusly formed polarizer. The polyvinyl alcohol film had been laminated to a polyester support with a dispersed, aqueous composition of polyvinyl alcohol or polyurethane on its surface.