Combinatorial evaluation system for thermal properties of glass materials using a vertical furnace with temperature gradient

Critical cooling rate Q for zinc terullite glass system is determined based on the time–temperature–transfer (T–T–T) diagrams, which are compiled by analyzing the crystallized area in the glass sample libraries annealed simultaneously by a furnace with temperature gradient. This method reduces the laborious routine work for preparation compared with the conventional one. Since the surface/volume ratio of the present samples is large, their crystallization is mainly governed by heterogeneous nucleation. Thus, the Q values in this study can be used as a practical index for the glass products whose surface should be free of being ground and/or polished, such as fire-polished lenses, optical fibers and waveguides.