Glass is a material you get by “melting and cooling,” but not every composition, and not every way of cooling, turns into glass. In ①, you decide the batch composition of SiO2, Al2O3, MgO, B2O3, Na2O, and K2O; work out the masses of the raw materials you actually weigh out (silica sand, carbonates, boric acid) and the amount of gas that escapes on heating; and mix them in a mortar. In ②, you heat the batch in an electric furnace and watch the decomposition of the carbonates (CO2 bubbles), the dissolution of the sand, bubble removal and homogenization, and the roles of Al and B in the network. In ③, you compare rapid and slow cooling and confirm that whether the melt crystallizes or becomes glass is decided by both the cooling rate and the composition.
Mochizuki Research Group, Tokyo University of Science | The three tabs carry over the state of one sample (the composition and mixing in ① → the melt in ② → the cooling in ③). How to read the numbers: Literature values with a source; Schematic educational rules that show a trend; Tentative values that need to be checked against Prof. Mochizuki’s materials or the literature. The cooling kinetics in ③ is quantitative only for the reference compositions with complete literature data; for any other composition it is schematic. The principles of the glass transition and crystallization are covered in Binary Phase Diagrams ④. Detailed explanations and sources are on the explanation page (in Japanese). Back to: Mochizuki Research Group Education — Inorganic Materials Science > Virtual Experiments, Inorganic Materials Science resources