Journal of Inorganic and Organometallic Polymers, Vol, 2, No. 1, 1992 Review Solid-State Thermochromism and Piezochromism in the Polysilylenes Frederic C. Schilling, l'3 Andrew J. Lovinger, 1 Don D. Davis, 1 Frank A. Bovey,1 and John M. Zeigler 2 Received April 29, 1991; revised August 19, 1991 The polysilylenes exhibit complex solid-state structures and electronic proper- ties. In this report the solid-state conformational structures of symmetrically substituted poly(di-n-alkylsilylenes) are described. Comparisons between the dif- ferent structures and their respective UV absorption characteristics demonstrate that the relationship is complex and aspects of molecular geometry beyond chain conformation must be considered. The thermochromic and piezochromic behavior of several of these polysitylenes is discussed. The all-tram conforma- tion of the silicon backbone is associated with both phenomena. The properties of several polysilylene copolymers have also been investigated. We find that some of the copolymers form a well-ordered structure and exhibit absorption characteristics similar to the crystalline phases of the corresponding homopolymers. KEY WORDS: Sigma-conjugated polymers; polymer conformation; UV absorption; thermochromism; piezochromism. INTRODUCTION During the past several years a significant amount of work has been reported concerning efforts to correlate the solid-state electronic properties of the polysilylenes with their conformational structures. In addition, a linkage was sought between the dramatic thermochromism observed for several of these polymers and changes in structures [1-6]. In this discus- sion we summarize the results of conformational analyses of a number of 1Polymer Chemistry Research Department, AT&T Bell Laboratories, Murray Hill, New Jersey 07974. 2 Silchemy Corp., Albuquerque, New Mexico 87112. 3To whom correspondence should be addressed at Room 1D-353, AT&T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974. 47 1053-0495/92/0300-0047506.50/0 © 1992 Plenum Pubhshmg Corporation