40,970 research outputs found
Assessing the network connectivity of modifier ions in metaphosphate glass melts: A dynamic light scattering study of Na-Zn mixtures
No full text16164503-164501; 164503-814
Fundementals of Condensed Mater and Crystalline Physics: An Introduction for students of Physics and Materials Science
No full text
Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics
No full text11-Oct1161-117022
Physical Review. B, Condensed Matter and Materials Physics
No full textThe viscoelastic relaxation of glass-forming (Na2O)x(P2O5)1−x liquids was measured by photon correlation spectroscopy at temperatures near the glass transition for compositions extending from pure phosphorus pentoxide to the metaphosphate (x=0.5). Over this compositional range, alkali addition produces a continuous depolymerization of the covalently bonded structure from one of a three-dimensional network to that of polymer chains. Substantial increases in the fragility accompany the depolymerization and are shown to be identical to those seen in certain ion-free chalcogenide glass formers suggesting the time scale for viscoelastic relaxation in network-forming liquids is controlled only by the topology of the covalent structure. The relaxation is nonexponential and the stretching exponent shows a complex variation with regards to both composition and temperature that is believed to arise from a decoupling of ionic motions from those of the network occurring as the glass transition is approached.6064201-0642078
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