Structural studies of reversible piezochromism in poly(alkylsilanes)

Studies of reversible piezochromism in polysilanes, first observed in poly(di n-hexylsilane) (PDHS) by Raman spectroscopy, have been extended to poly(di n-pentylsilane) (PDPS) and to the unsymmetrically substituted poly(n-pentyl n-hexylsilane) (PPHS). In all cases the piezochromic behavior has been investigated by UV-Vis, FTIR and Raman spectroscopies. Results indicate that at least three distinct molecular mechanisms are responsible for the observed shifts in UV-Vis absorptions as a function of pressure.