Regularities and Peculiarities of Solid Polydialkylsilane Order-Disorder Transitions as Studied by Optical (UV, Raman and IR) Spectroscopy

Abstract

As a result of systematic studies of numerous polydi-n-alkylsilane order-disorder transitions using a combination of UV, Raman, IR as well as XRD methods some generalizations are made concerning the nature of these processes. A criterion is proposed for a given UV band assignment to a given polymer modification based not only on its λ max value but also on the band width, contour and temperature behaviour of these parameters. Three types of ordering possible for these polymers were shown not to be necessarily interrelated. Side chain "melting" does not inevitably lead to thermochromism while thermochromic structural transitions can occur within the same phase.