Fluorescence anisotropy measurements of oriented polymers

Fluorescence anisotropy area scans of sheet and film specimens have been carried out using a fiber optic sensor that contains polarizing optical elements. Measurements on polyethylene terephthalate food packaging, which contains the fluorescent dye benzoxazolyl stilbene, are presented. In one case, a sheet cut from the side of a blow molded bottle displayed variation in biaxial orientation as a function of distance from the neck of the bottle. In another case, a thin film of shrink wrap material showed uniform biaxial orientation over the scanned area.