Optical properties of paraffin at temperature range from 40 to 80 °C

The transmittance spectrum of paraffin at temperature range from 40 to 80 °C was experimentally measured by a TU-19 FTIR spectrometer, and the optical constants of paraffin in the wavelength 250-850 nm were obtained based on transmittance spectra modeling. The optical properties of paraffin were calculated. The results show that the spectral transmittance of liquid paraffin in the region of UV and visible bands is bigger compared with solid paraffin. The extinction coefficients of the solid paraffin are between 1 × 10−5 and 3 × 10−5, and the refractive index of the solid paraffin decreases sharply with the wavelength increasing. Compared with solid paraffin, the extinction coefficients of liquid paraffin are smaller and the refractive index of liquid paraffin is mainly 1-1.4. And with the temperature increasing, the optical constants of liquid paraffin are different.