1. Below is a V-T cooling curve for a good glass former that is cooled from the liquid state at a fixed cooling ramp of 10°C/min. The letters on the ordinate correspond to reference temperatures on the cooling curve. Tm is the melting (or liquidus) point. Volume A + B + Tm F C D Temperature a) Which segment (as defined by the reference temperature range) of the cooling curve (if any) is most likely at thermodynamic equilibrium and why? (Specify the letters that correspond to endpoints of the cooling curve. That is, if your team argues that the entire cooling curve corresponds to thermodynamic equilibrium then the answer is "A-F"). Which range corresponds to metastableequilibrium (if any) and why? Which range is not at equilibrium? b)Which temperature or temperature range corresponds to the glass transition point or range? c) Sketch a cooling curve for the case where the liquid is cooled ay a ramp of (i) 20°C/min and (ii) 5°C/min. Describe the qualitative differences with the base curve of 10°C/min. d) Sketch likely V-T curves upon reheating the glass from temperature A to F for two cases, at (i) 20°C/min and (ii) 5°C/min. Describe the differences between the two cases and why. e) What happens to the glass if the cooling ramp is interrupted at temperature D and held?
