Polarized ultraviolet absorption of highly oriented poly(2-methoxy, 5-(2 '-ethyl)-hexyloxy)paraphenylene vinylene

Absorption spectra (2.0-6.1 eV) for poly[(2-methoxy, 5-(2'-ethyl)-hexyloxy) paraphenylene vinylene] oriented by gel processing in polyethylene show th at the bands peaking at 2.5, 3.6, and 6 eV are polarized parallel to the dr aw direction, while the band at 3.7 eV is polarized off axis. Although the onset of absorption in oriented samples is redshifted from that in disorder ed, spin-cast films, indicating significantly higher conjugation lengths, t he 3.6-eV band is present in both. Thus, the 3.6-eV band is an intrinsic fe ature of the electronic structure of the macromolecule and not a characteri stic of oligomers or polymers with short conjugation lengths. [S0163-1839(9 9)09707-6].