| Summary: | Many endothermic liquid–liquid transitions, occurring at a temperature T<sub>n+</sub> above the melting temperature T<sub>m</sub>, are related to previous exothermic transitions, occurring at a temperature T<sub>x</sub> after glass formation below T<sub>g</sub>, with or without attached crystallization and predicted by the nonclassical homogenous nucleation equation. A new thermodynamic phase composed of broken bonds (configurons), driven by percolation thresholds, varying from ~0.145 to Δε, is formed at T<sub>x,</sub> with a constant enthalpy up to T<sub>n+</sub>. The liquid fraction Δε is a liquid glass up to T<sub>n+</sub>. The solid phase contains glass and crystals. Molecular dynamics simulations are used to induce, in NiTi<sub>2</sub>, a reversible first-order transition by varying the temperature between 300 and 1000 K under a pressure of 1000 GPa. Cooling to 300 K, without applied pressure, shows the liquid glass presence with Δε = 0.22335 as memory effect and T<sub>n+</sub> = 2120 K for T<sub>m</sub> = 1257 K.
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