Wang, R. P.Smith, A.Luther-Davies, B.Kokkonen, H.Jackson, I.2015-12-172015-12-170021-8979http://hdl.handle.net/1885/95089We have prepared GeₓAsySe1−x−yglasses with mean coordination numbers (MCNs) from 2.2 to 2.86. Tg was found to generally increase with increasing MCN while the glass density showed a maximum at MCN≈2.45 and a minimum at MCN≈2.65. The elastic moduli of the glasses were estimated from the shear and compressional wave velocitiesmeasured by ultrasonic pulse interferometry. For the first time we simultaneously observed two elastictransition thresholds, the first at MCN≈2.45 and the second at MCN≈2.65, which appear closely correlated with changes in the glass microstructure. The elastic moduli of two groups of samples with the same MCN=2.4 and 2.64 but different compositions suggest that the chemical compositions also have an influence on the elastic properties.This research is supported by the Australian Research Council through its Centres of Excellence and Federation Fellow Programs.http://www.sherpa.ac.uk/romeo/issn/0021-8979..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 18/12/15). Copyright 2009 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics and may be found at https://doi.org/10.1063/1.3079806Keywords: Glass; Glass transition; Chemical compositions; Compressional wave velocities; Elastic properties; Glass densities; Glass microstructures; Mean coordination numbers; Ultrasonic pulse; Elastic moduli2009-03-1210.1063/1.30798062016-02-24