Evolution of the free enthalpy of mixing and its growth rate with various relaxation times: τ 1 = 10 − 4 (squares), τ 2 = 2 × 10 − 4 (diamonds), τ 3 = 4 × 10 − 4 (circles), and τ 4 = 8 × 10 − 4 (triangles), respectively.