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Elastic properties and short-range structural order in mixed network former glasses.
Weimin Wang1, Randilynn Christensen, Brittany Curtis
1Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan, USA. kieffer@umich.edu.
Physical Chemistry Chemical Physics : PCCP
|June 9, 2017
Summary
Elastic properties of alkali-containing glasses are crucial for structural integrity and ion mobility. This study reveals that a high density of network cations coordinated by four or more bridging oxygens enhances mechanical load transmission in sodium borosilicate and borogermanate glasses.
Area of Science:
- Materials Science
- Solid State Chemistry
- Glass Science
Background:
- Elastic properties of alkali-containing glasses are vital for understanding structural integrity, thermal conductivity, and ion mobility.
- Mixed-network former glass systems allow for systematic analysis of network structure's influence on properties by altering topology while keeping modifier concentration constant.
Purpose of the Study:
- To investigate the elastic properties of sodium borosilicate and sodium borogermanate glasses with varying network formers.
- To analyze the effect of network structure on elastic moduli and identify key structural features responsible for mechanical load transmission.
Main Methods:
- Synthesis and characterization of two mixed-network former glass systems: sodium borosilicate and sodium borogermanate.
- Measurement of elastic properties using Brillouin light scattering.
- Structural analysis using Nuclear Magnetic Resonance (NMR) spectroscopy.
- Development and application of a statistical thermodynamic reaction equilibrium model.
Main Results:
- Observed non-linear, non-additive mixed-glass former effects.
- Identified maxima in longitudinal, shear, and Young's moduli with increasing atomic number density.
- Determined the relative proportions of network structural units through combined spectroscopic and modeling approaches.
Conclusions:
- The predominant structural feature responsible for effective mechanical load transmission is a high density of network cations coordinated by four or more bridging oxygens.
- This coordination facilitates a three-dimensional network of covalent bonds, enhancing overall structural integrity and elastic performance.
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