Classification of secondary relaxation in glass-formers based on dynamic properties Export

@article{citeulike:332141, abstract = {Dynamic properties, derived from dielectric relaxation spectra of glass-formers at variable temperature and pressure, are used to characterize and classify any resolved or unresolved secondary relaxation based on their different behaviors. The dynamic properties of the secondary relaxation used include: (1) the pressure and temperature dependences; (2) the separation between its relaxation time and the primary relaxation time at any chosen ; (3) whether is approximately equal to the independent (primitive) relaxation time 0 of the coupling model; (4) whether both and 0 have the same pressure and temperature dependences; (5) whether it is responsible for the \"excess wing\" of the primary relaxation observed in some glass-formers; (6) how the excess wing changes on aging, blending with another miscible glass-former, or increasing the molecular weight of the glass-former; (7) the change of temperature dependence of its dielectric strength and across the glass transition temperature Tg; (8) the changes of and with aging below Tg; (9) whether it arises in a glass-former composed of totally rigid molecules without any internal degree of freedom; (10) whether only a part of the molecule is involved; and (11) whether it tends to merge with the -relaxation at temperatures above Tg. After the secondary relaxations in many glass-formers have been characterized and classified, we identify the class of secondary relaxations that bears a strong connection or correlation to the primary relaxation in all the dynamic properties. Secondary relaxations found in rigid molecular glass-formers belong to this class. The secondary relaxations in this class play the important role as a precursor or local step of the primary relaxation, and we propose that only they should be called the Johari\&\#150;Goldstein -relaxation. \©2004 American Institute of Physics.}, author = {Ngai, K. L. and Paluch, M.}, citeulike-article-id = {332141}, citeulike-linkout-0 = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JCPSA6000120000002000857000001&idtype=cvips&gifs=yes}, citeulike-linkout-1 = {http://link.aip.org/link/?JCP/120/857}, citeulike-linkout-2 = {http://dx.doi.org/10.1063/1.1630295}, doi = {10.1063/1.1630295}, journal = {The Journal of Chemical Physics}, keywords = {excess-wing, glass-forming-liquids, glycerol, pressure}, number = {2}, pages = {857--873}, posted-at = {2005-09-25 11:27:19}, priority = {2}, publisher = {AIP}, title = {Classification of secondary relaxation in glass-formers based on dynamic properties}, url = {http://dx.doi.org/10.1063/1.1630295}, volume = {120}, year = {2004} }

TY - JOUR ID - citeulike:332141 L3 - citeulike-article-id:332141 N2 - Dynamic properties, derived from dielectric relaxation spectra of glass-formers at variable temperature and pressure, are used to characterize and classify any resolved or unresolved secondary relaxation based on their different behaviors. The dynamic properties of the secondary relaxation used include: (1) the pressure and temperature dependences; (2) the separation between its relaxation time and the primary relaxation time at any chosen ; (3) whether is approximately equal to the independent (primitive) relaxation time 0 of the coupling model; (4) whether both and 0 have the same pressure and temperature dependences; (5) whether it is responsible for the "excess wing" of the primary relaxation observed in some glass-formers; (6) how the excess wing changes on aging, blending with another miscible glass-former, or increasing the molecular weight of the glass-former; (7) the change of temperature dependence of its dielectric strength and across the glass transition temperature Tg; (8) the changes of and with aging below Tg; (9) whether it arises in a glass-former composed of totally rigid molecules without any internal degree of freedom; (10) whether only a part of the molecule is involved; and (11) whether it tends to merge with the -relaxation at temperatures above Tg. After the secondary relaxations in many glass-formers have been characterized and classified, we identify the class of secondary relaxations that bears a strong connection or correlation to the primary relaxation in all the dynamic properties. Secondary relaxations found in rigid molecular glass-formers belong to this class. The secondary relaxations in this class play the important role as a precursor or local step of the primary relaxation, and we propose that only they should be called the Johari–Goldstein -relaxation. ©2004 American Institute of Physics. IS - 2 JF - The Journal of Chemical Physics EP - 873 TI - Classification of secondary relaxation in glass-formers based on dynamic properties PB - AIP VL - 120 SP - 857 KW - excess-wing KW - glass-forming-liquids KW - glycerol KW - pressure AU - Ngai, KL AU - Paluch, M PY - 2004/// UR - http://dx.doi.org/10.1063/1.1630295 ER -