A wealth of information on molecular dynamics lies buried in the shapes of infrared bands and Raman lines. Data obtained in the frequency domain has a counterpart in the time domain in the form of a time-correlation function, which is sensitive to molecular dynamics and relaxation processes in the picosecond time range. Band shape studies can provide information on rotational relaxation (usually in small molecules), the duration of “sticky” collisions (e.g., those involving hydrogen bonds), the dynamics of strong interactions, the coupling of local vibrations with lattice motions, and so on. Time correlation functions and their variation with temperature have been calculated for the modes observed near 1601 cm -1 and 1583 cm -1 in the infrared spectra of atactic polystyrene. The 1583 cm -1 band appears to be influenced by an anharmonic coupling to lower frequency modes that provides a mechanism of relaxation not allowed to the 1601 cm -1 band (for symmetry reasons). As a result, this mode is particularly sensitive to temperature, displaying changes in the relaxation time and second moments that show a transition near 80˚C, about 20˚C below the thermally observed T g. This mode is also inhomogeneously broadened as a result of slow transitions between domains of different mobility, supporting the view that glassy systems are dynamically heterogeneous. Plot of the correlation time, calculated for the 1601 cm -1 and 1583 cm -1 bands of atactic polystyrene, as a function of temperature. The lines have been placed only as a guide to the eye.The 1583 cm -1 mode is in Fermi resonance with a combination mode and is therefore more sensitive to vibrational relaxation through a transfer of energy to lattice modes. Relaxation processes change about 20˚C below the thermally observed T g. Vibrational Relaxation in Polymers Paul Painter, Penn State, DMR

Polymer Education – The Development of On- Line Courses Paul Painter and Mike Coleman, Penn State, DMR A number of institutions (including Penn State) that are now seriously considering making their courseware open-source. Taking advantage of recent advances in multimedia programs, particularly Flash 8 and 9 ©, we are in the process of constructing on-line lectures. The introduction to each lecture consists of a talking head video presentation which is coupled to Power Point type graphics (i.e. you get the lecturer plus the overheads in one presentation). In addition, you don’t need a “talking head”, but can do a voice-over on the animations created for our previously published CDs. (Most of each lecture is in this form, voice-over on animations, figures and “key-point” text.) These lectures will be placed on a website and can stream continuously to any computer that connects to the site This would benefit students in any setting, allowing a review of classroom lectures, freeing up class time for discussion, problem solving, etc. Our goal is to make this material open- source, freely available to anyone who wishes to use it. Screen capture of part of an on-line lecture on polymer chemistry.