Dynamic mechanical relaxation and loss in the incommensurate phase of quartz

The dynamic mechanical properties of quartz have been studied as a function of temperature across the αβ phase transition and in the vicinity of the incommensurate (IC) phase on cooling from the β phase. The mechanical response of the IC phase shows strong anelasticity for measurement of Youngs modulus (closely related to C ₁₁ in our geometry) with modulated stress driven at 1Hz. The dynamic shear modulus does not show similar strong effects in its imaginary component, although a very weak anomaly is barely detectable in the real part of the modulus. Our results indicate that the incommensurate microstructures within the quartz transition interval are susceptible to dilatational stress with relaxation times around 1s.