  We investigated temperature dependent optical conductivity spectra of
La_{7/8}Sr_{1/8}MnO_3. Its phonon bending mode starts to be splitted near a
structural phase transition temperature. With further cooling, strength of a
mid-infrared small polaron peak, which is located at 0.4 eV, becomes increased.
These temperature dependent changes in the phonon spectra and the polaron
absorption peaks were explained by a phase separation and a percolation-type
transition.
