CHEMISTRY AND TECHNOLOGY OF GLASS
Learning outcomes of the course unit
It is required an adequate understanding which may be based on the theoretical background acquired in the first cycle to extend its expertise in applying new approaches of critical analysis. In particular the candidates must have the capacity to address the issues in a multidisciplinary way with particular attention to the relationship between composition, industrial production and physical, chemical and mechanical properties of inorganic glass.
It is necessary the ability to clearly communicate the issues addressed during the course and to be able to correlate the various topics. It is needed to demonstrate the mastering and the proper planning of the study.It is positively evaluated the ability to update themes by consulting the specific scientific publications. (Learning Skills). It is necessary to demontrate a mature skillness in organizing the study with the formulation of original indivudual an individual course in taking on the skills introduced by the course. The visits of industrial plants are planned in order to have a direct experience of lecture concepts and production practices.
Course contents summary
Crystallization and glass transition. glass definition. glass transition Tg. Thermodynamic parameters of the glass transition. Transitions of the second order; definition of the glass structure, theoretical models. Parameter of Goldsmidth, Model of Zachariesen, Q parameter and connectivity. Theory of Dietzel, Lebedev model, boron glass (structural anomalies in the properties).
Crystallization in the glass; homogeneous, heterogeneous and epitaxial growth. Nucleation and growth rate of crystallization, the Tamman diagram. Kinetics of formation of TTT diagrams glasses.
Liquid-liquid immiscibility. Models of Bernal, Frenkel and Stewards, termodinamics of spinodal decomposition, binodale mode of immiscibility. Comparison between spinodal decomposition and nucleation. Phase diagrams (Na2O CaO-SiO2-Na2O-SiO2 and others)
Vycor glass. Glass production methods: sol-gel and melt synthesis: raw materials, gravimetric factor, solid state reactions, decomposition, fining agents. coloring agents SCHOTT catalogue. Industrial processes for the production of glass products. different types of furnaces and melting and refining stages. forming and annealing processes. Defects in glassy products; ropes, bubbles, crystalline inclusions, Glass ceramics; controlled crystallization, pyroceram, Macor, glass-ceramic applications.
Properties of glasses. Pseudoelestico viscosity behavior, equation of Vogel-Fulcher-Tamman. Dependence on the viscosity by temp. and its technological relevance. Viscosity and composition. Methods to determine the viscosity. Thermal expansion of Winkelman-Schott model. density of glass
electrical properties, and ionic conductivity dependence on composition.
Mechanical properties of surface cracks glass, analysis of cracks for chemical bath, Young's modulus, thermal and chemical processes of tempering. Optical properties of the silica glass, the transmission spectrum. Refractive index and its dependence on composition. molar rifrectivity, reflection, dispersion. chromatic aberration, Abbe Number, flint and crown glass. Refractometer V-block. Opals
Chalcogenide glasses, structure, composition, synthesis processes, applications and properties.
Optical fibers, different types of optical fibers, production techniques. Bioactive glasses, glassware 45S5. Metal glasses, mechanical properties, critical parameters for glass production
Introduction to Glass Science and Technology. by J. E. Shelby
Royal Society of Chemistry
Fundamentals of Inorganic Glasses
Author: Arun Varshneya
The lessons will be carried out by illustrating the concepts summarized in the slides. To give aclear explanation of some steps of industrial production of glass products, films will be screened. Visits to glassware plants and research institutes will be planned to see systems for the production of unconventional glass materials. Seminars are also provided by experts in the production of traditional glass materials.
Assessment methods and criteria
The evaluation procedure consists of an oral test that is composed by two main phases: the first involves the dissertation of a subject chosen by the student. The topic can be any of the various chapters in the course (from theory to application) and exposure can only be based on the provided teaching material. Otherwise,the student can get a more detailed kowledge of the subject with additional material found by bibliographic research. This last indication is not mandatory but the student's faculty on the basis of his / her degree of interest in the subject chosen may lead to further elements that could only have been mentioned in lesson. In the second phase, the teacher will ask questions concerning the rest of the program for testing the knowledge of the various aspects of the Chemistry and Technology of Glassy Materials by exploring the acquired skills both for the theoretical part and for the technological part. In particular, it is a matter of evaluation of the candidate's ability to expose the arguments using correct terminology and to be able to assume specific knowledge independently.