Millennial Special Leading Papers on Ceramics in the 20<sup>th</sup> Century: the Best of JCerSJ Studies on the Conditions of Glass Formation

Abstract

This paper has the following key features. Systematic research on the many types of multicomponent (mainly ternary components) glass formation ranges, such as borate, silicate, germanate, vanadate and tellurite systems, revealed the conditions for multicomponent glass formation. Although the conditions for monocomponent glass formation identified by Zachariasen have been acknowledged since 1932, the conditions for multicomponent glass formation were not proposed at that time. Imaoka introduced general rules for the conditions of multicomponent glass formation on the basis of Zachariasen's rule. The adaptability of these conditions was confirmed by later research. Preciously, the glass formation probability of arbitrary compositions had only been judged by the melting method, but the application of general rules by Imaoka allowed predictions for glass formation possible without experimentation, and this allowed tremendous time savings during the planning of glass compositions.The establishment of multicomponent glass forming conditions clarified, to a certain extent, the relationship between the glass compositions and the glass structure. Therefore, the multicomponent glass forming conditions have been extremely useful in research on material design to predict the relationship between physical properties and the glass structure. Thus, it is now possible to target the research objectives more precisely and save considerable research time. Although not all commercial glass components can be judged by the conditions examined in this study, it is considered to be a reasonable reference for the discussion of commercial glass components.The above-mentioned features have contributed enormously to the research and technological development of glass.