Entropy-dominated Dissipation in Sapphire Compressed Dynamically from 14 to 87 GPa

States reached by dynamic compression are governed by free energy in which dissipative energy is --TS, where T is temperature and S is entropy. In a liquid like Ar effective pair interaction enegy is $\sim $0.01 ev. As a result Ar is relatively compressible with a shock rise time of $\sim $0.5 ps and 2.2 fold compression at a T of 14,000 K at 50 GPa. Thermal energy is $\sim $90{\%} of shock energy. Entropy changes are small in a shocked fluid and dissipative energy appears primarily as T. We have measured wave profiles of sapphire with elastic strength of $\sim $15 GPa in three different crystal orientations at shock stresses of 14, 24, and 87 GPa. At 24 GPa the rise time of the plastic wave is $\sim $300 ns, 5 orders of magnitude greater than in liquid Ar. At 50 GPa sapphire is compressed 1.1 fold to a T of $\sim $500 K. Thermal pressures are negligible and bond strengths are $\sim $1 ev, about 2 orders of magnitude greater than in Ar. Bonds in sapphire probably break over $\sim $10s of ns. This long rise time causes quasi-isentropic compression with negligible shock heating. Dissipative energy goes primarily into the entropy of disordering the strong 3-D lattice, rather than into T.