Observation of in-plane optical anisotropy of spin-cast rigid-rod electroluminescent polymer films

Transmittance difference spectroscopy has been applied to study the optical properties of spin-cast rigid-rod polymer films. Significant in-plane opti cal anisotropy is observed for both the real and the imaginary parts of the transmittance of the poly(2,5-pyridine diyl) films. This in-plane optical anisotropy is a result of the partial alignment of the polymer chains, orie nted radially outward from the center of the film, during the spin casting process. This observation has important implications for emissive polymer d evices, particularly for devices sensitive to polarization direction and th ose using waveguide confinement where relatively long propagation distance within the films are required. (C) 2000 American Institute of Physics. [S00 03-6951(00)04411-9].