The Department of Physics & Astronomy hosts guest speaker Hillary L. Smith, Assistant Professor of Physics at Swarthmore College. Her presentation is on the topic ‘‘The Race to Beat Crystallization: the Thermodynamics of Glasses.’’
This lecture is free and open to the public, and will be presented as a Zoom webinar; register online.
Thermodynamic properties of materials play a key role in understanding the conduction of heat and electrons. Experimental probes of entropy and heat capacity help elucidate these properties and can be used to inform the development of new materials. In this talk, I will describe an investigation of the contributions to entropy in several types of glasses. Glasses are solids, like crystals, but isotropic and without long-range order, like liquids. Not all materials are capable of forming a glass. Among those that do, some form quite easily, and others must be cooled extremely quickly- as fast as 100,000 K/sec- to avoid becoming crystalline. Glasses also have a special glass transition temperature, hundreds of degrees below where the solid melts, at which the hard glass becomes viscous. My work investigates the origin of the entropy and heat capacity at the glass transition. Our experimental results have given new support to decades-old theories. I will show results from my laboratory at Swarthmore College and from measurements at the Spallation Neutron Source in Oak Ridge, TN.