The Precise Determination of Thermal Conductivity of Pure Fused Quartz

The temperature dependence of the thermal conductivity of pure fused quartz is measured precisely over the temperature range 0° to 500°C. The results obtained are among the most reliable since the experimental accuracy is estimated to be ±1.5% and the purity of the fused quartz sample was 99.97%, exceeding the purity of the more than fifteen investigations previously published. A newly designed apparatus is used, employing a ``dual combined method'' in which thermal conductivity values are simultaneously obtained by both absolute and comparative methods. The thermal conductivity of fused quartz increases smoothly with increasing temperature.