Direct methods of observing non-standard oxygen species in oxide glasses and crystals
Abstract/Contents
- Abstract
- Glasses are amorphous solids that lack long-range order but contain short-range order with varying degrees of polymerization. This short-range order is comprised of varying oxygen species made from a combination of oxygen and one or more network-forming cations, which bond strongly to oxygen, and network-modifying cations, which bond weakly. This thesis focuses on four oxygen species in particular, non-bridging oxygens (NBO) which are oxygen anions shared between one network-former and one or more network-modifiers, bridging oxygens (BO), which are oxygen anions shared between two network-formers, tricluster oxygens, which are oxygen anions shared between three tetrahedral network-formers, and free oxide ions (FO) which are oxygen anions with exclusively network-modifiers as neighbors. 17O NMR can be used to directly view and measure the ratios of these various species, which can yield information about glass structure and properties. This work explores how oxygen-17 NMR can be used as a tool to probe oxide glass structure across a variety of compositions. A variety of oxide glasses were synthesized and enriched in 17O, including glasses containing various combinations of Al, B, and Si, which have diverse industrial applications. The goal of this work was to study species of oxygen that are rarely found within many compositions of oxide glasses, which was accomplished, in part, through the implementation of new double resonance NMR techniques involving decoupling of quadrupolar nuclides. Chapters 2 and 3 aimed to study relative proportions of NBO and BO in glass structures, focusing particularly on isolating the presence of the rare, but important, Al-NBO species. In Chapter 2, the TRAPDOR technique was introduced and first implemented with the dephasing of oxygen connected to either 27Al or 11B from observed 17O spectra in a variety of calcium aluminosilicate and aluminoborosilicate glasses. Chapter 3 continues and expands this research to calcium aluminoborate, aluminosilicate and aluminoborosilicate glasses, and barium aluminoborosilicate glasses, and quantifies the effect of a number of experimental variables in the design of complex TRAPDOR NMR experiments. Chapter 4 looks at tricluster oxygens in crystalline and glassy strontium tetraborate through 17O MQMAS, looking at differences in structure between the crystal and equivalent glass. Appendix XI looks at FO in crystals and low-silica Mg-rich glasses with 17O-> 29Si HETCOR NMR.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2018; ©2018 |
| Publication date | 2018; 2018 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | LaComb, Michelle Marie |
|---|---|
| Degree supervisor | Stebbins, Jonathan Farwell |
| Thesis advisor | Stebbins, Jonathan Farwell |
| Thesis advisor | Cegelski, Lynette |
| Thesis advisor | Mao, Wendy (Wendy Li-wen) |
| Degree committee member | Cegelski, Lynette |
| Degree committee member | Mao, Wendy (Wendy Li-wen) |
| Associated with | Stanford University, Department of Geological Sciences. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Michelle Marie LaComb. |
|---|---|
| Note | Submitted to the Department of Geological Sciences. |
| Thesis | Thesis Ph.D. Stanford University 2018. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2018 by Michelle Marie LaComb
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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