STRUCTURE, COMPOSITION, AND VIBRATIONAL PROPERTY OF IODINE-DOPED POLYVINYL-ALCOHOL STUDIED BY TEMPERATURE-DEPENDENT I-K-EDGE EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE

The temperature dependence of the I K-edge extended X-ray absorption f ine-structure (EXAFS) spectra of a highly oriented iodine-containing p olyvinyl alcohol (I-PVA) him was investigated in order to reveal any l ocal structures around I. It was firstly demonstrated that an analysis of the EXAFS amplitude, which is associated with the Debye-Waller fac tor (mean square relative displacement) provides information concernin g the composition ratio of the dopant species. In the present high-con trast I-PVA film it was found that a significant amount (64%) of isola ted I- is present, and that the polyiodine species, which contributes to a high polarization property of I-PVA for ultraviolet and visible l ight, consists of 21% Is and 15% I-5(-), without containing neutral I- 2.