Atomic Structural Origin of Fictive Temperature Revealed by AZnP3O9 (A = K, Rb) Glasses

The fictive temperature (Tf) is widely applied to understand the relaxation thermodynamics of a glass; however, its atomic structural origin is still unclear. Here, we report two novel AZnP3O9 glasses obtained by melting the composition identical single crystals. These glasses exhibit structural inheritance within 5 Å from the single crystal counterparts that is quantified by δ = nglass/ncry (0 ≤ δ ≤ 1, n is the number of pair correlation functions). Among the available glass-formers, glassKZnP3O9 exhibits the highest structural inheritance (δ = 1, nglass = 8). More insightfully, a reverse correlation between δ and the relaxation thermodynamic parameters is observed in glassAZnP3O9, revealing for the first time the atomic structural origin of fictive temperature.