Building and Breaking Bonds by Homogenous Nucleation in Glass-Forming Melts Leading to Transitions in Three Liquid States

The thermal history of melts leads to three liquid states above the melting temperatures T(m) containing clusters—bound colloids with two opposite values of enthalpy +Δε(lg) × ΔH(m) and −Δε(lg) × ΔH(m) and zero. All colloid bonds disconnect at T(n+) > T(m) and give rise in congruent materials, through a first-order transition at T(LL) = T(n+), forming a homogeneous liquid, containing tiny superatoms, built by short-range order. In non-congruent materials, (T(n+)) and (T(LL)) are separated, T(n+) being the temperature of a second order and T(LL) the temperature of a first-order phase transition. (T(n+)) and (T(LL)) are predicted from the knowledge of solidus and liquidus temperatures using non-classical homogenous nucleation. The first-order transition at T(LL) gives rise by cooling to a new liquid state containing colloids. Each colloid is a superatom, melted by homogeneous disintegration of nuclei instead of surface melting, and with a Gibbs free energy equal to that of a liquid droplet containing the same magic atom number. Internal and external bond number of colloids increases at T(n+) or from T(n+) to T(g). These liquid enthalpies reveal the natural presence of colloid–colloid bonding and antibonding in glass-forming melts. The Mpemba effect and its inverse exist in all melts and is due to the presence of these three liquid states.