"Glasses are ubiquitous in nature. Window glasses, which are made of silica, are the most common example. However, there exist many different examples, chalcogenide glasses and metallic glasses to name a few, whose properties come to the fore in different contexts. Glasses are one of the oldest artificial materials used by humankind; the oldest glasses known so far were found in the deserts of Egypt. People have been making and using glass for thousands of years and attempts to improve on this process and to produce glasses with desired properties are some of the earliest at- tempts to better understand this material. The empirical knowledge that glasses are made by cooling liquids quickly begs far more questions than it gives answers. Fore- most among these, in the scope of statistical physics, is the question of whether the transformation of liquids to glasses upon cooling is a thermodynamic transition. A considerable amount of effort has been devoted to answering this question - and this question is also the focus of this thesis. Glasses are similar to crystalline solids, in the sense that they are mechanically rigid and capable of supporting load. On the other hand, the microscopic structure of glasses is disordered, similar to that of liquids. This mixed character of glasses makes it difficult to distinguish it from liquids, purely based on structure, and from crystalline solids, based on mechanical response to external forces.
A hallmark property of glasses is that the relaxation time (the time to reach equilibrium) of the system is much larger than the typical duration of experiments or of numerical simulations.
Glasses can be obtained by cooling a liquid. Typically, a liquid crystallises when cooled below its melting temperature. However, if one can avoid crystallisation some- how (sufficiently rapid cooling or ""quenching"" is one of the common ways), the liquid will reach a metastable or supercooled state below its melting temperature. If one decreases the temperature further, viscosity increases rapidly in a small temperature interval. As a result, the dynamics of the liquid becomes too sluggish to explore all possible particle arrangements over an accessible timescale."
By:
Monoj Adhikari Imprint: Mohammed Abdul Sattar Dimensions:
Height: 279mm,
Width: 216mm,
Spine: 11mm
Weight: 472g ISBN:9798224716777 Pages: 198 Publication Date:29 March 2024 Audience:
General/trade
,
ELT Advanced
Format:Paperback Publisher's Status: Active