Infrared Emission Spectra of Quartz*

Abstract

Infrared emission spectra of quartz have been recorded and analyzed. The spectra were taken every 0.2 sec on the materials heated under ablating conditions in an arc wind tunnel. Surface temperatures near 2400°K are deduced and emissivity values for the corresponding highly viscous state are estimated. The enhancement of the emissivity at wavelengths below 4.5 μ by the use of “white” quartz is reported. Details of the scanning spectrometer (sweep rate 3.5 μ/0.2 sec) and application to measurement of surface temperatures are presented.