• Research Areas
• Glasses and Amorphous Oxides
  • Aluminosilicate Glass Structure
  • Borosilicate Glass Structure
  • Pressure effects on glass and melt structure
  • Insulating coatings for microelectronics
  • Amorphous metal oxides for optical coatings
• Order/Disorder in Minerals and Ceramic Materials
• Dynamics in Crystalline and Molten Silicates and Oxides

Borosilicate Glass Structure

Multi-component borosilicate glasses have many applications, such as fiber reinforcements in composites, in flat-panel display screens for computers and cell phones, and in nuclear waste sequestration. These materials are structurally intriguing, and particularly versatile, because the coordination of the boron network cations readily varies from 3 to 4 depending on composition and temperature, having important consequences for properties. We have a major, ongoing project to examine effects of these variables on network coordination and connectivity. We are exploring the large differences caused by varying the size and charge of the "network modifier" cations (e.g. Na+ vs. Ca2+), B/Si ratio, and Al content. Below are shown some of the dramatic effects on boron coordination of the fictive temperature, as determined by cooling rate and measurements by differential scanning calorimetry (DSC).