Questions:
Imagine making a close-packed material by filling a container with 20-μm-diameter glass spheres. You then heat this "material" for 12 × 103 seconds at 650°C and the "material" shrinks by 5 vol%. You take an identical sample and find that the same shrinkage is achieved in 360 seconds at 700°C. Assuming that the surface energy of the glass is 0.3 J/m2, calculate the viscosity of the glass at each temperature and deduce an activation energy.