ELECTROABSORPTION MEASUREMENTS OF THE EMERALDINE BASE FORM OF POLYANILINE

Electroabsorption measurements have been performed on the polymeric em eraldine base form of polyaniline and a related phenyl-capped tetramer . The spectra run from the near infrared to the UV, encompassing the m ain low energy absorption peaks of the materials. The lineshapes of th e spectra closely resemble each other, indicating that the electronic structure of the two are similar. The results also indicate that the s tate produced upon 2 eV photoexcitation is, to some degree, spatially extended. The data for the phenyl-capped tetramer show a small signal below the main peak in the electroabsorption which could possibly be a ssigned to a transition of oscillator strength to a normally optically forbidden transition.