Time and ensemble averaged dynamic light scattering in orthoterphenyl above and below the glass transition
- Advanced Materials Lab., Albuquerque, NM (United States)
- Kansas State Univ., Manhattan, KS (United States). Dept. of Physics
While traditional dynamic light scattering is useful for following structural relaxation in the liquid, in the glassy domain the technique is limited by the ultimate patience of the experimentalist; i.e., the structural relaxation can not be measured when the experimental time scale is less than the structural relaxation time. Nevertheless, the authors show how useful information regarding structural relaxation can be accessed from light scattering in the glass using a novel ensemble-averaged technique. Dynamic light scattering (DLS) measurements performed on glass forming orthoterphenyl show an inequality between time and ensemble average correlation functions near and below the calorimetric glass transition temperature, T{sub g}, and hence demonstrate ergodicity breaking. The ensemble averaged measurements provide a measure of the so-called non-ergodicity parameter, f{sub q}, below T{sub g}. The DLS results for orthoterphenyl indicate that the functional form for f{sub q} is consistent with Mode Coupling theory predictions, but occurs at the glass transition temperature, T{sub g} = 243 K, rather than at T{sub c} {approx} 290 K as observed in neutron scattering studies.
- OSTI ID:
- 580877
- Report Number(s):
- CONF-961202-; ISBN 1-55899-359-2; TRN: IM9807%%71
- Resource Relation:
- Conference: 1996 Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 2-6 Dec 1996; Other Information: PBD: 1997; Related Information: Is Part Of Structure and dynamics of glasses and glass formers; Angell, C.A. [ed.] [Arizona State Univ., Tempe, AZ (United States)]; Ngai, K.L. [ed.] [Naval Research Lab., Washington, DC (United States)]; Kieffer, J. [ed.] [Univ. of Illinois, Urbana, IL (United States)]; Egami, T. [ed.] [Univ. of Pennsylvania, Philadelphia, PA (United States)]; Nienhaus, G.U. [ed.] [Univ. of Ulm (Germany)]; PB: 530 p.; Materials Research Society symposium proceedings, Volume 455
- Country of Publication:
- United States
- Language:
- English
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