The polydiacetylenes are a class of polymers that are attrac- ting increasing attention worldwide. There are many reasons for this interest one of the most important being the availability of many polydiacetylenes as macroscopic, high quality, single crystals. This fact was first reported in the pioneering work of Prof. G. Hegner on the solid-state polymerization of disub- stituted diacetylenes in the late 1960s. Since then studies of the polymerization process and the properties of monomers and polymers have advanced understanding of solid-state reactivity and the physiCS of quasi-one-dimensional materials. More recently work on soluble polydiacetylenes, gels and films has been of interest for both academic and technological reasons. Progress in this area has required a combination of research disciplines ranging from synthetic organic chemistry to solid- state physics. The interdisciplinary effort required for success- ful research in polydiacetylenes was reflected in the mix of chemists, physicists and materials scientists who attended the Workshop. The emerging potential for commercial applications of polydiacetylenes was also evident in the nearly equal partici- pation of academic and industrial/government scientists. The WOrkshop was the first major international meeting to focus solely on polydiacetylenes. It provided a forum in which problems of mutual interest could be discussed by scientists with diverse backgrounds and interests. It also satisfied the need for a review of the science of these materials at a time when this basic understanding is leading to technological applications.

Table of Contents:
Diacetylene Polymerization Kinetics.- Solid State Photopolymerization of Diacetylenes.- Photopolymerization Reaction Intermediates in Diacetylene Crystals.- Structural Study of the Topochemical Polymerization of Two Diacetylenes.- Microstructures and Polymer Chain Length in Diacetylene Single Crystals.- X-Ray Topographic Studies of the Solid-State Polymerization of PTS[2,4-Hexadiyne Diol Bis(p-Toluene Sulphonate)].- Electronic Structure of Conjugated Polymers.- Theoretical Exciton and Polariton Spectra of Polydiacetylenes.- Ab Initio Studies on Polyynes and Polydiacetylenes: Structure and Harmonic Force Field.- Structural Dependence of the Longitudinal Electric Polarizability of Finite Polyene Chains: An ab Initio Study.- Electrical Transport and Doping of Polydiacetylenes.- The Ultra High Electron Mobility on Polydiacetylene Chains: The Theory.- Electron Motion in Polydiacetylene: The Facts.- Electric Field Dependence of Diffusion and Trapping in Polydiacetylene.- The Study of Electronic Excitations of Polydiacetylenes by Optical and Resonance Raman Spectroscopy.- Electric-Field Sensitive Defect States in Fully and Partially Polymerized PTS.- Spectroscopic Studies of a Diacetylenic Surfactant.- Optical Properties of Polyacetylene.- Spectroscopy and Kinetics of a Planar-Nonplanar Conformational Transition in Polydiacetylene Solutions.- Polydiacetylene Macromolecules in Solution: Rods, Coils and Gels.- 1,4-Diphenylbutenyne: A Model Compound for Polydiacetylenes (PDA).- Toward Polydiacetylenes as Utile Optical and Electronic Elements.- Electric Field Induced Optical Second Harmonic Generation and Polarization Effects in Polydiacetylene Films.- Third Harmonic Generation and Two Photon Absorption in a Polydiacetylene Solution.- Mechanical and Structural Properties of Polydiacetylenes.- Polymerized Diacetylene Monomers in Monolayer and Multilayer Films, Characterization and Possible Applications.- Diacetylenic Phospholipid Polymers.- Homoepitaxy and in-Plane Anisotropy in Langmuir-Blodgett Films.- Working Group Reports.