# Nano-phase separation and structural ordering in silica-rich mixed network former glasses

Hao Liu, Randall E. Youngman, Saurabh Kapoor, Lars Rosgaard Jensen, Morten Mattrup Smedskjær, Yuanzheng Yue

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

2 Citationer (Scopus)

### Resumé

We investigate the structure, phase separation, glass transition, and crystallization in a mixed network former glass series, i.e., B 2O 3-Al 2O 3-SiO 2-P 2O 5 glasses with varying SiO 2/B 2O 3 molar ratio. All the studied glasses exhibit two separate glassy phases: droplet phase (G 1) with the size of 50-100 nm and matrix phase (G 2), corresponding to a lower calorimetric glass transition temperature (T g1) and a higher one (T g2), respectively. Both T g values decrease linearly with the substitution of B 2O 3 for SiO 2, but the magnitude of the decrease is larger for T g1. Based on nuclear magnetic resonance and Raman spectroscopy results, we infer that the G 1 phase is rich in boroxol rings, while the G 2 phase mainly involves the B-O-Si network. Both phases contain BPO 4- and AlPO 4-like units. Ordered domains occur in G 2 upon isothermal and dynamic heating, driven by the structural heterogeneity in the as-prepared glasses. The structural ordering lowers the activation energy of crystal growth, thus promoting partial crystallization of G 2. These findings are useful for understanding glass formation and phase separation in mixed network former oxide systems, and for tailoring their properties.

Originalsprog Engelsk Physical Chemistry Chemical Physics 20 23 15707-15717 11 1463-9076 https://doi.org/10.1039/c8cp01728j Udgivet - 22 maj 2018

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Silicon Dioxide
Phase separation
silicon dioxide
Glass
Crystallization
glass
crystallization
Oxides
Nuclear magnetic resonance spectroscopy
magnetic resonance spectroscopy
Raman spectroscopy
Glass transition
Substitution reactions
glass transition temperature
Activation energy
crystal growth
Heating
substitutes
activation energy
nuclear magnetic resonance

### Citer dette

@article{c582ac9e2fb34c78b4439c3200598fb2,
title = "Nano-phase separation and structural ordering in silica-rich mixed network former glasses",
abstract = "We investigate the structure, phase separation, glass transition, and crystallization in a mixed network former glass series, i.e., B 2O 3-Al 2O 3-SiO 2-P 2O 5 glasses with varying SiO 2/B 2O 3 molar ratio. All the studied glasses exhibit two separate glassy phases: droplet phase (G 1) with the size of 50-100 nm and matrix phase (G 2), corresponding to a lower calorimetric glass transition temperature (T g1) and a higher one (T g2), respectively. Both T g values decrease linearly with the substitution of B 2O 3 for SiO 2, but the magnitude of the decrease is larger for T g1. Based on nuclear magnetic resonance and Raman spectroscopy results, we infer that the G 1 phase is rich in boroxol rings, while the G 2 phase mainly involves the B-O-Si network. Both phases contain BPO 4- and AlPO 4-like units. Ordered domains occur in G 2 upon isothermal and dynamic heating, driven by the structural heterogeneity in the as-prepared glasses. The structural ordering lowers the activation energy of crystal growth, thus promoting partial crystallization of G 2. These findings are useful for understanding glass formation and phase separation in mixed network former oxide systems, and for tailoring their properties.",
author = "Hao Liu and Youngman, {Randall E.} and Saurabh Kapoor and Jensen, {Lars Rosgaard} and Smedskj{\ae}r, {Morten Mattrup} and Yuanzheng Yue",
year = "2018",
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Nano-phase separation and structural ordering in silica-rich mixed network former glasses. / Liu, Hao; Youngman, Randall E.; Kapoor, Saurabh; Jensen, Lars Rosgaard; Smedskjær, Morten Mattrup; Yue, Yuanzheng.

I: Physical Chemistry Chemical Physics, Bind 20, Nr. 23, 22.05.2018, s. 15707-15717.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Nano-phase separation and structural ordering in silica-rich mixed network former glasses

AU - Liu, Hao

AU - Youngman, Randall E.

AU - Kapoor, Saurabh

AU - Jensen, Lars Rosgaard

AU - Smedskjær, Morten Mattrup

AU - Yue, Yuanzheng

PY - 2018/5/22

Y1 - 2018/5/22

N2 - We investigate the structure, phase separation, glass transition, and crystallization in a mixed network former glass series, i.e., B 2O 3-Al 2O 3-SiO 2-P 2O 5 glasses with varying SiO 2/B 2O 3 molar ratio. All the studied glasses exhibit two separate glassy phases: droplet phase (G 1) with the size of 50-100 nm and matrix phase (G 2), corresponding to a lower calorimetric glass transition temperature (T g1) and a higher one (T g2), respectively. Both T g values decrease linearly with the substitution of B 2O 3 for SiO 2, but the magnitude of the decrease is larger for T g1. Based on nuclear magnetic resonance and Raman spectroscopy results, we infer that the G 1 phase is rich in boroxol rings, while the G 2 phase mainly involves the B-O-Si network. Both phases contain BPO 4- and AlPO 4-like units. Ordered domains occur in G 2 upon isothermal and dynamic heating, driven by the structural heterogeneity in the as-prepared glasses. The structural ordering lowers the activation energy of crystal growth, thus promoting partial crystallization of G 2. These findings are useful for understanding glass formation and phase separation in mixed network former oxide systems, and for tailoring their properties.

AB - We investigate the structure, phase separation, glass transition, and crystallization in a mixed network former glass series, i.e., B 2O 3-Al 2O 3-SiO 2-P 2O 5 glasses with varying SiO 2/B 2O 3 molar ratio. All the studied glasses exhibit two separate glassy phases: droplet phase (G 1) with the size of 50-100 nm and matrix phase (G 2), corresponding to a lower calorimetric glass transition temperature (T g1) and a higher one (T g2), respectively. Both T g values decrease linearly with the substitution of B 2O 3 for SiO 2, but the magnitude of the decrease is larger for T g1. Based on nuclear magnetic resonance and Raman spectroscopy results, we infer that the G 1 phase is rich in boroxol rings, while the G 2 phase mainly involves the B-O-Si network. Both phases contain BPO 4- and AlPO 4-like units. Ordered domains occur in G 2 upon isothermal and dynamic heating, driven by the structural heterogeneity in the as-prepared glasses. The structural ordering lowers the activation energy of crystal growth, thus promoting partial crystallization of G 2. These findings are useful for understanding glass formation and phase separation in mixed network former oxide systems, and for tailoring their properties.

U2 - 10.1039/c8cp01728j

DO - 10.1039/c8cp01728j

M3 - Journal article

VL - 20

SP - 15707

EP - 15717

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 23

ER -