Using an optical pyrometer for temperature measurements of shock-compressed polytetrafluoroethylene

Optical pyrometry is used to determine the shock-compression temperature of up to 51 GPa of polytetrafluoroethylene – a highly light scattering polymer in the uncompressed state. Conditions are considered under which the relative spectral characteristics of the radiating layer of shock-compressed polytetrafluoroethylene are close to the spectral characteristics of the scattered radiation detected from the end of the sample. A pyrometer for measuring the ratio of spectral radiances at four wavelengths from the range of 380–630 nm is described. The measured relative spectral radiances were approximated by the Planck curve normalized to unity at a wavelength of 630 nm. The approximation suggests that the detected radiation is of thermal nature. The average temperature from four experiments is 3100 $\pm$ 200 K. The measured temperature is compared with the results of previous calculations.