title: Topology and glass structure evolution in (BaO)x((B₂O₃)₃₂(SiO₂)₆₈)(100-x) ternary--evidence of rigid, intermediate, and flexible phases.
abstract: We examine variations in the glass transition temperature (T(g)(x)), molar volume (V(m)(x)), and Raman scattering of titled glasses as a function of modifier (BaO) content in the 25% < x < 48% range. Three distinct regimes of behavior are observed; at low x, 24% < x < 29% range, the modifier largely polymerizes the backbone, T(g)(x) increase, features that we identify with the stressed-rigid elastic phase. At high x, 32% < x < 48% range, the modifier depolymerizes the network by creating non-bridging oxygen (NBO) atoms; in this regime T(g)(x) decreases, and networks are viewed to be in the flexible elastic phase. In the narrow intermediate x regime, 29% < x < 32% range, T(g)(x) shows a broad global maximum almost independent of x, and Raman mode scattering strengths and mode frequencies become relatively x-independent, V(m)(x) show a global minimum, features that we associate with the isostatically rigid elastic phase, also called the intermediate phase. In this phase, medium range structures adapt as revealed by the count of Lagrangian bonding constraints and Raman mode scattering strengths.
authors.affiliation: AFRL/RYDP, 2241 Avionics Circle, B620, Wright-Patterson AFB, Ohio 45433-7707, USA.
authors.forename: C
authors.initials: C
authors.lastname: Holbrook
authors.affiliation: Department of Electrical and Computing Systems, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio 45221-0030, USA.
authors.forename: Shibalik
authors.initials: S
authors.lastname: Chakraborty
authors.affiliation: Department of Electrical and Computing Systems, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio 45221-0030, USA.
authors.forename: S
authors.initials: S
authors.lastname: Ravindren
authors.affiliation: Department of Electrical and Computing Systems, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio 45221-0030, USA.
authors.forename: P
authors.initials: P
authors.lastname: Boolchand
authors.affiliation: AFRL/RXAN, 3005 Hobson Way, B651, Wright-Patterson AFB, Ohio 45433-7707, USA.
authors.forename: Jonathan T
authors.initials: JT
authors.lastname: Goldstein
authors.affiliation: AFRL/RXAN, 3005 Hobson Way, B651, Wright-Patterson AFB, Ohio 45433-7707, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Stutz