Thermal conductivity and heat capacity of amorphous SiO₂: pressure and volume dependence

The thermal conductivity ( lambda ) and heat capacity per unit volume ( rho c p ) of amorphous SiO 2 have been measured under hydrostatic pressure up to 1 GPa at room temperature using a transient two-strip method. The thermal conductivity was found to decrease slightly with increasing pressure. For the volume dependence of lambda expressed by the Bridgman parameter, g=-( delta ln lambda / delta ln V) T , the authors obtained g=-1.5. The experimental value of g is discussed in conjunction with predicted g-values based on theoretical models of lambda (T). The specific heat capacity (c p ) calculated from measured rho c p was found to be almost constant with increasing pressure.