John C. Mauro

Pennsylvania State University | Penn State · Department of Materials Science and Engineering

Glasses are typically formed by melt-quenching, that is, cooling of a liquid on a timescale fast enough to avoid ordering to a crystalline state, and formerly thought to comprise three categories: inorganic (non-metallic), organic and metallic. Their impact is huge, providing safe containers, allowing comfortable and bright living spaces and even u...

The availability of water and the type of interlayer anions present affect the arrangement and interlayer spacing of layered double hydroxide (LDH). A systematic study of the effect of relative humidity (RH) on the basal spacing of phosphate intercalated, magnesium aluminum LDHs (MgAl–PO4 LDH) was conducted, confirming that MgAl‐PO4 LDH exhibit dis...

The sodium aluminosilicate (NAS) glass family is important for many different industrial applications, but glass relaxation has not yet been thoroughly studied in this system. Thermal analysis techniques such as differential scanning calorimetry (DSC) and modulated differential scanning calorimetry (MDSC) can provide insight into the enthalpy relax...

This presentation deals with Ion Exchange in silicate glasses and discusses the effects on glass surfaces coming from thermodynamics, kinetics, and surface mechanics issues. A contribution from the thermodynamics of irreversible processes is discussed to clarify some interdiffusion past results and a surface kinetics model is proposed to overpass t...

Glasses formed from transition metal oxides have shown tailorable electrical and optical properties depending on the valence state and individual element. Vanadate glasses have received specific attention for their high conductivities as compared to most glass families. In this study, the frequency‐dependent capacitance and direct current (dc) cond...

The common feature of non‐ergodic systems is an internal timescale that greatly exceeds the external observational timescale tobs${t}_{obs}$. This kinetic state of broken ergodicity occurs in many systems, with profound thermodynamic implications. In this work, we present a review of non‐ergodic physical systems focused on the common origins of non...

This is the fourth in this series of “Lessons Learned and Yet to be Learned” on topics related to glass strength.(1–3) In this paper we pick up the topic of stronger glass products from our earlier publication(2) and expand to discussing commercial technologies. Included in this discussion are a brief historical perspective of the initial technolog...

A recent study showed that generating local crystalline paths within a glassy matrix provides only a moderate increase in thermal conductivity until the path fills most of the total volume. It was indicated that percolation theory governs the thermal conductivity in such crystalline‐implanted glass composites. In this study, we use computer simulat...

Decarbonizing the glass industry requires alternative melting technology, as current industrial melting practices rely heavily on fossil fuels. Hydrogen has been proposed as an alternative to carbon‐based fuels, but the ensuing consequences on the mechanical behavior of the glass remain to be clarified. A critical distinction between hydrogen and c...

In 2022, 150 million tons of glass was produced globally, and approximately 47% of that amount was glass hollowware for tableware and food, beverage, and cosmetics packaging. Glass is considered one of the most recyclable materials as its properties and performance do not degrade upon reheating and reforming; yet only 21% of global production is re...

Topological constraint theory has emerged as a rapid, predictive method to quantify the relationship between structural rigidity and glass properties. Understanding the structure of telluro‐vanadate (TeO 2 –V 2 O 5 ) glasses has remained difficult owing to their complex mixture of structural units. Here, we propose a topological model that accurate...

Alkali and alkaline earth elements play a crucial role in the structure, processing, and properties of bioactive glasses, widely used in medical applications since their inception in 1969.

The energy landscape represents a high‐dimensional mapping of the configurational states of an atomic system with their respective energies. Under isobaric conditions, enthalpy landscapes can be used to account for volumetric changes of the system. Understanding the energy or enthalpy landscape holds the key for discovering materials with targeted...

This article reviews promising studies on the design, manufacturing, microstructure, properties, and applications of glass-ceramics containing ZrO2 and relevant glass-ceramic matrix composites. After the addition of ZrO2 to a glass-ceramic composition, it can persist in the residual glassy phase, facilitate nucleation, and/or precipitate as ZrO2 or...

Previous research has shown a consistent discrepancy in the reported structure of alkaline earth aluminosilicate glasses using molecular dynamics (MD) simulations versus nuclear magnetic resonance (NMR) experiments. Past MD results have consistently shown less than 5% five‐coordinated Al units (Al[5]) in peraluminous glass compositions, but with hi...

Both unwanted and induced crystallization can impact bioactivity, physical and mechanical properties of bioactive glasses (BGs). Uncontrolled crystallization has negative consequences, rendering BGs unreliable. However, by manipulating the type, size, shape, and quantity of crystals in BGs, plenty of opportunities arise for controlling, for example...

The thermodynamics and kinetics of interdiffusion are analyzed for the case of glass ion exchange, a process by which alkali ions from a glass inter‐diffuse with different, usually larger, alkali ions from a surrounding salt bath. The spontaneity of the ion exchange reaction is driven by entropy production. This paper details the first derivation a...

The field strength effect on fracture toughness was tested for three alkaline earth (AE) aluminoborosilicate (ABS) glasses. This work explores the impact of modifier field strength (FS) on macro‐mechanical properties in line with previous works which examined the FS effect on structure, hardness, crack resistance, and elastoplastic properties of al...

Bioactive glasses (BGs) are known for their selective ability to (i) form a mechanically strong interfacial bond with hard (bone) or soft tissues (gingivae or cartilages) (i.e., silica-, silica-phosphate-, phosphate-, borate-phosphate-, or silica-phosphate-borate-based BGs); or (ii) serve as reservoirs for fast-release of therapeutic (osteogenic, a...

The mixed modifier effect (MME) is one of the most challenging puzzles in the field of oxide glasses, as there exists no universal quantitative theoretical model for accurately describing and predicting the nonlinear deviation of property values. In this paper, pairwise and ternary interactions are examined experimentally to understand the MME in a...

There is a growing demand for high-performance infrared (IR) materials with longer wavelength optical transmission, higher mechanical strength, and increased thermal stability. Although crystalline materials, namely transparent ceramics, have shown suitable optical properties, they are difficult and expensive to produce, making glasses more attract...

Glass properties are governed by the interplay between network formers and network modifiers; for a given composition of network formers, the ratio of different cationic modifiers compensating the anionic species in the network has a profound effect, which is often nonlinear, called a mixed modifier effect (MME). We have investigated the MME of sod...

Aqueous stability is a critical property for the application of metal-organic framework (MOF) materials in humid conditions. The sampling of the free energy surface for a water reaction is challenging due to a lack of a reactive force field. Here, we developed a ReaxFF force field for simulating the reaction of zeolitic imidazole frameworks (ZIFs)...

Indentation has been widely used for investigating the mechanical behavior of glasses. However, how the various microscopic properties (such as atomic structure and mechanics) of glass evolve from the immediate contact with the indenter to the far‐field regions, and how these observables are correlated to each other remain largely unknown. Here, us...

This article examines various methods for evaluating the impact of journals in the ceramic sciences, including the H-index, journal impact factor (JIF), and the recently introduced MZE-index (defined by Montazerian–Zanotto–Eckert). We evaluate the performance of 31 reputable journals in ceramic science and technology and find that the JIF and H-ind...

The field strength (FS) effect of six different network modifiers on the elastoplastic properties of aluminoborosilicate glasses was explored using a volumetric recovery study. This work, in conjunction with Part I, explored the intersection of hardness, crack resistance, and other physical properties with glass elasticity. Results showed that (1)...

Indentation has been widely used for investigating the mechanical behavior of glasses. However, how the various microscopic properties (such as atomic structure and mechanics) of glass evolve from the immediate contact with the indenter to the far-field regions, and how these observables are correlated to each other remain largely unknown. Here, us...

The modifier field strength (FS) is believed to play an important role in determining the elastic–plastic responses of aluminoborosilicate (ABS) glasses, but its effect is not well understood. Three novel alkali and three alkaline earth (AE) ABS compositions were created for this study which is the first part of two studies that explored the elasto...

Understanding the mechanisms contributing to dielectric properties of glasses is critical for designing new compositions for microwave frequency applications. In this work, dielectric permittivity was measured using a cavity perturbation technique at 10 GHz for a series of niobiosilicate glasses with the compositions (100‐2x)SiO2‐ xNb2O5‐ xLi2O whe...

Bioactive glasses (BGs) and glass-ceramics (BGCs) have become a diverse family of materials being applied for treatment of many medical conditions. The traditional understanding of bioactive glasses and glass-ceramics pins them to bone-bonding capability without considering the other fields where they excel, such as soft tissue repair. We attempt t...

The impact of microstructure on hardness in phase‐separated calcium aluminosilicate glasses is investigated. Changes in hardness are governed by microstructure deformations that occur during indentation. Phase separation leads to decreased hardness due to the incongruent yielding of the droplet and matrix phases. Moreover, the deformation of micros...

Predicting the effects of ceramic microstructures on macroscopic properties, such as the Knoop hardness, has long been a difficult task. This is particularly true in glass–ceramics, where multiple unique crystalline phases can overlap with a background glassy phase. The combination of crystalline and glassy phases makes it difficult to quantify the...

At least 25 bioactive glass (BG) medical devices have been approved for clinical use by global regulatory agencies. Diverse applications include monolithic implants, bone void fillers, dentin hypersensitivity agents, wound dressing, and cancer therapeutics. The morphology and delivery systems of bioactive glasses have evolved dramatically since the...

Achieving thinner and higher performance display/substrate glasses and transparent glass-ceramics with tunable properties requires a precise control of acid-etching process, thus necessitating a comprehensive understanding of glass composition–structure–dissolution behavior relationships in acidic medium. Unfortunately, the literature on this subje...

Although glass–ceramics have been widely explored for their thermal stability and mechanical properties, they also offer unique symmetry‐dependent properties such as piezoelectricity and pyroelectricity through controlled crystallization of a polar phase. This work examines crystallization of LiNbO3 in a 35SiO2–30Nb2O5–35Li2O mol% composition and c...

Nano/micron-sized bioactive glass (BG) particles are attractive candidates for both soft and hard tissue engineering. They can chemically bond to the host tissues, enhance new tissue formation, activate cell proliferation, stimulate the genetic expression of proteins, and trigger unique an-ti-bacterial, anti-inflammatory, and anti-cancer functional...

Bioactive glasses (BGs) and glass-ceramics (BGCs) have become a diverse family of materials being applied for treatment of many medical conditions. The traditional understanding of bioactive glasses and glass-ceramics pins them to bone-bonding capability without considering the other fields where they excel, such as soft tissue repair. We attempt t...

Our previous work proposed a phase reaction equation for the current lithium disilicate (LD) glass-ceramic system containing lithium tantalate (LT) as a secondary phase: 2(Li2SiO3) + Ta2O5 → Li2Si2O5 + 2(LiTaO3). The present study had a goal of finding support for the proposed equation by examining the effect of the ratio of [SiO2] to [Li2O] on the...

Dental glass-ceramics (DGCs) are developed by controlled crystallization of oxide glasses and form an important group of biomaterials used in modern dentistry. They are also of great importance to scientists studying the fundamentals of crystallization. DGCs must meet strict requirements for restorative prostheses and to streamline the workflow for...

Although the interactions among glass formers and modifiers, for example, connectivity and charge distribution, have been studied extensively in oxide glasses, the impact of a particular modifier species on the mechanical performance of aluminoborosilicate (ABS) glasses is not well understood. This work compares the indentation properties of six AB...

The heat dissipation of silicate glasses draws much attention for various applications, and the desire for glasses with high thermal conductivity remains an unsolved challenge. The structural origin of thermal conductivity in glass remains not fully understood. The present study aims to elucidate the impact of embedding highly thermally conductive...

The Glass Genome has only started to be explored. To advance the next generation design of glasses, both physics-informed and data-driven models must be widely available and understood. The most common difficulty in materials modeling is determining which are the simplest approaches appropriate for understanding and predicting key properties. The s...

The presence of large scatter in linear response data has cast doubt on the existence of an inverse correlation between liquid fragility and nonexponentiality, as originally proposed by Böhmer et al. [J. Chem. Phys. 99, 4201 (1993)]. We present a model for the temperature dependence of the stretching exponent based on the MYEGA model for supercoole...

Nucleation is one of the primary contributions to the microstructure of glass-ceramics. However, the nucleation process within glass-ceramics is not understood across all glass systems, nor is the specific role of nucleating agents. The present article proposes a comprehensive definition of a nucleating agent: “a nucleating agent is a minority comp...

Lithium aluminosilicate glass‐ceramics are well known for good transparency, high fracture toughness, low thermal expansion, and good ion exchange ability. In this study, new transparent Li2O‐Al2O3‐SiO2 (LAS) glass‐ceramics with petalite and β‐spodumene solid solution as the major crystalline phases were invented for favorable mechanical properties...

A knowledge of fluctuations is crucial for understanding the long-term kinetics of glasses. However, current approaches for modeling relaxation rely on an order parameter that only approximates the physics of relaxation. In this work, we compare a standard relaxation model with a newly proposed model in terms of their ability to capture the evoluti...

Thermal treatments of ion‐exchanged glasses are often needed for postprocessing steps, including deposition or curing of inorganic or organic coatings deposited on the glass surface. In this study, we investigate the effects of post–ion exchange thermal treatment on the concentration profile, residual stress, and final strength of the ion‐exchanged...

The present study examines the Knoop hardness (HK) via microindentation of lithium disilicate (LD) glass-ceramics that contain lithium tantalate (LT) as a secondary phase. A 64-sample data set was analyzed to study the relationship between the phase assemblage and the mechanical property. It was found that the HK was dependent on the phase assembla...

Future research is envisaged in which the compositional and microstructural design, synthesis, characterization, and application of biomaterials can be significantly accelerated by theoretical and computational modeling. In the last 25 years, more than 6000 articles and 100 review papers have highlighted the importance of discovering bioactive glas...

Atomic structure dictates the performance of all materials systems; the characteristic of disordered materials is the significance of spatial and temporal fluctuations on composition-structure-property-performance relationships. Glass has a disordered atomic arrangement, which induces localized distributions in physical properties that are conventi...

Nucleation is of great interest to materials scientists, physicists, and chemists studying fundamental scientific aspects of this phenomenon, as well as engineers working to develop glass-ceramics. Fundamental research in this field is indispensable for understanding the nature of the glassy state and the development of new products such as nanostr...

We synthesized two series of bimetallic (zinc and cobalt) zeolitic imidazolate frameworks (ZIF-62) under different solvothermal conditions. It is found that the structure of the derived ZIF crystals is highly sensitive to synthesis conditions. One series possesses the standard ZIF-62 structure, whereas the other has a mixed structure composed of bo...

Color is an important property of lithium disilicate (LD) glass–ceramics for a variety of applications. For example, the color of dental glass–ceramics needs to be tuned to match the color of natural teeth. The present study examines the optical properties of LD glass–ceramics containing lithium tantalate as a secondary phase via ultraviolet–visibl...

Aluminosilicate glasses are ubiquitous in high‐performance displays due to their favorable thermal, mechanical, and optical properties. They also exhibit interesting structural features depending on the ratio of alumina to modifiers in the glass system. Excess modifiers exist in the metaluminous region, while the peraluminous region contains more n...

Glasses are materials that lack a crystalline microstructure and long-range atomic order. Instead, they feature heterogeneity and disorder on superstructural scales, which have profound consequences for their elastic response, material strength, fracture toughness and the characteristics of dynamic fracture. These structure-property relations prese...

Glass has provided many life‐changing products over the past millennia to improve the quality of human living. In this “International Year of Glass 2022” paper, we review the applied science and technology of indentation and abrasion damage in glass, highlighting its practical importance for commercial products. We briefly review what has already b...