The water content in seven glass samples from the K/T boundary on Haiti was determined by micro-infrared spectrometry. These glasses are thought to result from impact melting associated with the K/T boundary impact, although this interpretation is not unanimous. The results of the water determinations, 0.013-0.021 wt% H20, show that the Haiti glasses are water-poor. This is a common characteris...

In situ AC nanocalorimetry was used to characterize vapor-deposited glasses of six mono- and di-alcohol molecules. Benzyl alcohol glasses with high kinetic stability and decreased heat capacity were prepared. When annealed above the glass transition temperature Tg, transformation of these glasses into the supercooled liquid took 103.4 times longer than the supercooled liquid relaxation time (τα...

The molecular dynamics (MD) computer simulation technique has been used to study the structure of lithium aluminosilicate (LAS) glasses and the diffusion of lithium ions. Five kinds of lithium aluminosilicate glasses with different R (ratio of the concentration of Al to Li) values are simulated. The structural features of the simulated glasses are analyzed using Radial Distribution Functions (R...

The relaxation spectrum of glassy solids has long been used to probe their dynamic structural features and the fundamental deformation mechanisms. Structurally complicated glasses, such as molecular glasses, often exhibit multiple relaxation processes. By comparison, metallic glasses have a simple atomic structure with dense atomic packing, and their relaxation spectra were commonly found to be...

Materials with disordered structures have a crucial role in the rapid development of new technologies. Improvement of these materials for particular application, as well as preparation of novel composites is based on a thorough understanding of the basic mechanisms of charge carrier transport. Among various classes of structurally disordered materials, a family of iron phosphate glasses attract...

Raman and calorimetric studies on GexSe1−x glasses have provided evidence for the existence of the intermediate phase (IP) in chalcogenide and other glasses. Ab initio molecular dynamics models of these glasses are discussed, and an atomistic picture of the IP, based upon the models and available experiments is presented. Analysis of our models reveals that the IP in GexSe1−x glasses appears du...

We find that the density dependence of the glass transition temperature of Lennard-Jones (LJ) and Weeks-Chandler-Andersen (WCA) systems can be predicted from properties of the zero-temperature (T=0) glasses. Below a crossover density ρs, LJ and WCA glasses show different structures, leading to different vibrational properties and consequently making LJ glasses more stable with higher glass tran...

Glasses are materials that are much more common in our daily life than one might naively expect. Apart from the obvious (inorganic) glasses, such as wine glasses, bottles and windows, we also have the organic (often polymeric) glasses, such as most plastic materials (bags, coatings, etc.). In the last few years also metallic glasses have come to our daily (St. Andrews) life since they are used,...

In order to fabrication of transparent glass-ceramics with Li-mica nano crystals, the glasses with chemical composition of 94.9 mass% Li(1+x)Mg3AlSi3(1+x)F2 (x=0.5) with 5.1 mass% MgF2 were crystallized. The glasses were fabricated via the conventional melt-quenching technique. Mica crystals were precipitated in the glass phase by later heat treatment. Glass samples had glass transition tempera...

The 0.5Na2S + 0.5[xGeS2 + (1 - x)PS5/2] mixed glass former (MGF) glass system exhibits a nonlinear and nonadditive negative change in the Na(+) ion conductivity as one glass former, PS5/2, is exchanged for the other, GeS2. This behavior, known as the mixed glass former effect (MGFE), is also manifest in a negative deviation from the linear interpolation of the glass transition temperatures (T(g...