Electroabsorption spectrum of substituted polyphenylacetylenes

Electroabsorption (EA) measurements on thin films of poly [o-(trimethylsilyl) phenylacetylene] and poly [o-(trimethylsilylmethyl) phenylacetylene] have been performed. The spectral change induced by an exernal electric field (EA spectra) has been observed, which shows the similar shape of the second derivative of the optical absorption spectra. The change in the absorption Δα is obtained from the EA spectrum, and Δn is calculated through Kramers-Krong transformation. The optical properties of substituted polyphenylacetylenes (PPAs) were discussed.