Self-Diffusion of Supercooled <i>o</i>-Terphenyl near the Glass Transition Temperature

@article{citeulike:2453930, abstract = {Abstract: Self-diffusion coefficients for the low molecular weight glass former o-terphenyl have been measured near Tg by isothermally desorbing thin film bilayers of deuterio and protio o-terphenyl in a vacuum chamber. We observe translational diffusion that is about 100 times faster at Tg + 3 K than the Stokes-Einstein prediction. Predictions from random first order transition theory and a dynamic facilitation approach are in reasonable agreement with our results; in these approaches, enhanced translational diffusion is associated with spatially heterogeneous dynamics. Self-diffusion controls crystallization in o-terphenyl for most of the supercooled liquid regime, but at temperatures below Tg + 10 K, the reported crystallization rate increases suddenly while the self-diffusion coefficient does not. This work and previous work on trisnaphthylbenzene both find a self-diffusion-controlled crystal growth regime and an enhancement in self-diffusion near Tg, suggesting that these phenomena are general characteristics of fragile low molecular weight glass formers. We discuss the width of the relaxation time distributions of o-terphenyl and trisnaphthylbenzene as they relate to the observation of enhanced translational diffusion.}, address = {Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706}, author = {Mapes, M. K. and Swallen, S. F. and Ediger, M. D. }, citeulike-article-id = {2453930}, doi = {10.1021/jp0555955}, journal = {J. Phys. Chem. B}, keywords = {diffusion, ediger, supercooled}, month = {January}, number = {1}, pages = {507--511}, posted-at = {2008-03-01 22:46:44}, priority = {2}, title = {Self-Diffusion of Supercooled <i>o</i>-Terphenyl near the Glass Transition Temperature}, url = {http://dx.doi.org/10.1021/jp0555955}, volume = {110}, year = {2006} }

TY - JOUR ID - citeulike:2453930 L3 - citeulike-article-id:2453930 TI - Self-Diffusion of Supercooled <i>o</i>-Terphenyl near the Glass Transition Temperature JF - J. Phys. Chem. B VL - 110 IS - 1 SP - 507 EP - 511 AD - Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 N2 - Abstract: Self-diffusion coefficients for the low molecular weight glass former o-terphenyl have been measured near Tg by isothermally desorbing thin film bilayers of deuterio and protio o-terphenyl in a vacuum chamber. We observe translational diffusion that is about 100 times faster at Tg + 3 K than the Stokes-Einstein prediction. Predictions from random first order transition theory and a dynamic facilitation approach are in reasonable agreement with our results; in these approaches, enhanced translational diffusion is associated with spatially heterogeneous dynamics. Self-diffusion controls crystallization in o-terphenyl for most of the supercooled liquid regime, but at temperatures below Tg + 10 K, the reported crystallization rate increases suddenly while the self-diffusion coefficient does not. This work and previous work on trisnaphthylbenzene both find a self-diffusion-controlled crystal growth regime and an enhancement in self-diffusion near Tg, suggesting that these phenomena are general characteristics of fragile low molecular weight glass formers. We discuss the width of the relaxation time distributions of o-terphenyl and trisnaphthylbenzene as they relate to the observation of enhanced translational diffusion. KW - diffusion KW - ediger KW - supercooled AU - Mapes, MK AU - Swallen, SF AU - Ediger, MD PY - 2006/01/12/ UR - http://dx.doi.org/10.1021/jp0555955 ER -