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Glass Science and First-Order Transitions at a Turning Point
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Glass Science and First-Order Transitions at a Turning Point

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Smart Materials".

Deadline for manuscript submissions: closed (20 December 2022) | Viewed by 9725

Special Issue Editors

Dr. Robert F. Tournier

E-Mail Website
Guest Editor
1. University Grenoble Alpes, LNCMI, 38042 Grenoble, CEDEX 09, France
2. CNRS, Institut Neel, 38042 Grenoble, CEDEX 09, France
Interests: amorphous materials; glasses; vitrification; homogeneous nucleation; spin glasses; superconducting materials; melt memory; unmelted crystals; overheating
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Michael I. Ojovan

E-Mail Website
Guest Editor
Department of Materials, Imperial College London, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
Interests: amorphous and crystalline materials; glass transition; vitrification; nuclear waste management; immobilisation; radiation effects
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Freezing transitions in amorphous materials are well known, while more and more thermodynamic transitions are observed in many investigations. Why? Polyamorphism exists depending on the thermal history, and on the heating and cooling rates. Glacial phases with highest Tg are formed at various cooling rates or by isothermal annealing. Ultrastable glass phases are obtained by vapor deposition below Tg. Are these glass phases formed below or above Tg, linked by some common thermodynamic and structural parameters? The first-order transitions simulated in liquid elements look like glacial phase transitions at high heating rates. Is the first-order transition to 4He glass-phase under pressure, a unique example? A change at glass transition leads to a new liquid phase. How to rejuvenate a melt which is characterized by a new Tg? This melt memory could exist up to a temperature higher than Tm. Meantime, liquid–liquid transitions are observed above Tm. Are they related to medium-range order, to short-range order, to some structural memory and to a hidden undercooled phase which could be overheated? Are prefrozen layers in polymers, due to this memory or only the consequence of 2D confinement near substrates? Are homogeneous nucleation phenomena able to describe these new transitions?

Is it possible for superclusters depending on thermal history and acting as bricks of glass formation in melts, to induce glass transitions at various percolation thresholds? What are the topological characteristics of liquid and glassy phases and how do they evolve during transitions observed?

These and some other related questions may serve as starting points for preparing submissions to this Special Issue of Materials by MDPI.

Dr. Robert F. Tournier
Prof. Dr. Michael I. Ojovan
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • glass transition
  • stable glasses
  • glacial phases
  • increasing Tg
  • melt Melt rejuvenation
  • liquid mean-range and short-range orders
  • first-order transitions in melts
  • prefrozen layers
  • melt-memory
  • relaxation from quenched melts toward Tg
  • MD simulations
  • nucleation phenomena
  • topology

Published Papers (5 papers)

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Research

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15 pages, 8818 KiB  
Article
Assigning Viscosity Values in the Glass Softening Temperature Range
by Miguel O. Prado and Franco E. Benedetto
Materials 2023, 16(4), 1596; https://doi.org/10.3390/ma16041596 - 14 Feb 2023
Viewed by 1254
Abstract
A new optical method for assigning glass viscosity values in the softening temperature range is presented. In this method, an irregular particle, a few millimeters in size, laying on an alumina plate, is heated up to temperature T, and then remains at [...] Read more.
A new optical method for assigning glass viscosity values in the softening temperature range is presented. In this method, an irregular particle, a few millimeters in size, laying on an alumina plate, is heated up to temperature T, and then remains at this temperature. T should be within the softening temperature range of the glass. There are no external applied shear stresses, the only acting shear forces are those coming from the particle’s own surface energy. At the fixed temperature T, the surface free energy of the sample decreases by viscous flow while its shape evolves from a polyhedron or irregular shape towards a spherical or rounded shape. This shape evolution is recorded using a photographic camera. From each image, the sample’s roundness is determined, obtaining a characteristic time τ from the roundness against time. Simultaneously, using the available software, a value for the viscosity η was calculated, at temperature T, allowing for building sets of T, τ, η, namely three data values. Accordingly, if T, τ are considered as independent variables, a master function η = η (T, τ) can be built. Now, if we measure T, τ data on a glass of an unknown viscosity, the master function makes it possible to assign a η value. When incipient crystallization or liquid–liquid phase separations are present, effective viscosity values are obtained. This method requires a high temperature microscope, as well as tridimmensional samples with a few cubic millimeters of volume. Each isothermal τ determination can take from minutes to several hours. We tested the method with two glasses of known viscosity values: borosilicate glass (VG98) and alumimoborosilicate glass (SG7), both of which are used for radioactive waste immobilization and have assigned log(η) values between 6 and 7.3 with η in Pa s. The discrepancy between the log(η) values assigned here and those values fitted with a VFT function on the values measured for the SG7 and VG98 glasses were within ±14%. Full article
(This article belongs to the Special Issue Glass Science and First-Order Transitions at a Turning Point)
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15 pages, 4006 KiB  
Article
Effect of Dolomite Addition on the Structure and Properties of Multicomponent Amphibolite Glasses
by Adrian Nowak, Malgorzata Lubas, Jaroslaw Jan Jasinski, Magdalena Szumera, Renata Caban, Jozef Iwaszko and Kamila Koza
Materials 2022, 15(14), 4870; https://doi.org/10.3390/ma15144870 - 13 Jul 2022
Cited by 3 | Viewed by 1241
Abstract
The structure and properties of the glass can be modified by introducing appropriate additives. Dolomite is one of the primary raw materials modifying the properties of glass, in which the essential component is calcium-magnesium double carbonate CaCO3∙MgCO3. The paper [...] Read more.
The structure and properties of the glass can be modified by introducing appropriate additives. Dolomite is one of the primary raw materials modifying the properties of glass, in which the essential component is calcium-magnesium double carbonate CaCO3∙MgCO3. The paper presents the research results on glasses obtained by smelting pure amphibolite and amphibolite modified with 10 and 20% dolomite additives. The raw material used was mined in the Poland region of Lower Silesia. The glass melting process was carried out in an electric furnace at 1450 °C for 2 h. The structure and properties of the glasses and crystallization products were determined by Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy—Energy Dispersive Spectroscopy (SEM-EDS). Viscosity and Vickers microhardness were also measured. It was found that the modification of amphibolite glass by adding dolomite affects the glasses’ properties and structure. The research results determined the effect of dolomite addition on the properties of alumino-silicate glasses in terms of the mineral fibre products used in the construction industry. Full article
(This article belongs to the Special Issue Glass Science and First-Order Transitions at a Turning Point)
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21 pages, 32432 KiB  
Article
Prediction of Second Melting Temperatures Already Observed in Pure Elements by Molecular Dynamics Simulations
by Robert F. Tournier and Michael I. Ojovan
Materials 2021, 14(21), 6509; https://doi.org/10.3390/ma14216509 - 29 Oct 2021
Cited by 9 | Viewed by 1484
Abstract
A second melting temperature occurs at a temperature Tn+ higher than Tm in glass-forming melts after heating them from their glassy state. The melting entropy is reduced or increased depending on the thermal history and on the presence of antibonds or [...] Read more.
A second melting temperature occurs at a temperature Tn+ higher than Tm in glass-forming melts after heating them from their glassy state. The melting entropy is reduced or increased depending on the thermal history and on the presence of antibonds or bonds up to Tn+. Recent MD simulations show full melting at Tn+ = 1.119Tm for Zr, 1.126Tm for Ag, 1.219Tm for Fe and 1.354Tm for Cu. The non-classical homogeneous nucleation model applied to liquid elements is based on the increase of the Lindemann coefficient with the heating rate. The glass transition at Tg and the nucleation temperatures TnG of glacial phases are successfully predicted below and above Tm. The glass transition temperature Tg increases with the heating rate up to Tn+. Melting and crystallization of glacial phases occur with entropy and enthalpy reductions. A universal law relating Tn+ and TnG around Tm shows that TnG cannot be higher than 1.293Tm for Tn+= 1.47Tm. The enthalpies and entropies of glacial phases have singular values, corresponding to the increase of percolation thresholds with Tg and TnG above the Scher and Zallen invariant at various heating and cooling rates. The G-phases are metastable up to Tn+ because the antibonds are broken by homogeneous nucleation of bonds. Full article
(This article belongs to the Special Issue Glass Science and First-Order Transitions at a Turning Point)
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22 pages, 10611 KiB  
Article
Building and Breaking Bonds by Homogenous Nucleation in Glass-Forming Melts Leading to Transitions in Three Liquid States
by Robert F. Tournier and Michael I. Ojovan
Materials 2021, 14(9), 2287; https://doi.org/10.3390/ma14092287 - 28 Apr 2021
Cited by 11 | Viewed by 2141
Abstract
The thermal history of melts leads to three liquid states above the melting temperatures Tm containing clusters—bound colloids with two opposite values of enthalpy +Δεlg × ΔHm and −Δεlg × ΔHm and zero. All colloid bonds disconnect at [...] Read more.
The thermal history of melts leads to three liquid states above the melting temperatures Tm containing clusters—bound colloids with two opposite values of enthalpy +Δεlg × ΔHm and −Δεlg × ΔHm and zero. All colloid bonds disconnect at Tn+ > Tm and give rise in congruent materials, through a first-order transition at TLL = Tn+, forming a homogeneous liquid, containing tiny superatoms, built by short-range order. In non-congruent materials, (Tn+) and (TLL) are separated, Tn+ being the temperature of a second order and TLL the temperature of a first-order phase transition. (Tn+) and (TLL) are predicted from the knowledge of solidus and liquidus temperatures using non-classical homogenous nucleation. The first-order transition at TLL gives rise by cooling to a new liquid state containing colloids. Each colloid is a superatom, melted by homogeneous disintegration of nuclei instead of surface melting, and with a Gibbs free energy equal to that of a liquid droplet containing the same magic atom number. Internal and external bond number of colloids increases at Tn+ or from Tn+ to Tg. These liquid enthalpies reveal the natural presence of colloid–colloid bonding and antibonding in glass-forming melts. The Mpemba effect and its inverse exist in all melts and is due to the presence of these three liquid states. Full article
(This article belongs to the Special Issue Glass Science and First-Order Transitions at a Turning Point)
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Review

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25 pages, 3871 KiB  
Review
Structural Changes in Metallic Glass-Forming Liquids on Cooling and Subsequent Vitrification in Relationship with Their Properties
by D. V. Louzguine-Luzgin
Materials 2022, 15(20), 7285; https://doi.org/10.3390/ma15207285 - 18 Oct 2022
Cited by 17 | Viewed by 2481
Abstract
The present review is related to the studies of structural changes observed in metallic glass-forming liquids on cooling and subsequent vitrification in terms of radial distribution function and its analogues. These structural changes are discussed in relationship with liquid’s properties, especially the relaxation [...] Read more.
The present review is related to the studies of structural changes observed in metallic glass-forming liquids on cooling and subsequent vitrification in terms of radial distribution function and its analogues. These structural changes are discussed in relationship with liquid’s properties, especially the relaxation time and viscosity. These changes are found to be directly responsible for liquid fragility: deviation of the temperature dependence of viscosity of a supercooled liquid from the Arrhenius equation through modification of the activation energy for viscous flow. Further studies of this phenomenon are necessary to provide direct mathematical correlation between the atomic structure and properties. Full article
(This article belongs to the Special Issue Glass Science and First-Order Transitions at a Turning Point)
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