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Diffuse reflectance and transmittance of IR absorbing polymer film
Author(s) -
Ho WenDar,
Ma ChenChi M.,
Wu LiehChun
Publication year - 1998
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.10337
Subject(s) - transmittance , materials science , diffuse reflection , attenuation coefficient , molar absorptivity , reflectivity , optics , absorption (acoustics) , diffuse reflectance infrared fourier transform , polymer , irradiation , composite material , optoelectronics , chemistry , biochemistry , physics , photocatalysis , nuclear physics , catalysis
Abstract This study employs the ray tracing method to analyze and develop mathematical formulae for the internal reflectance of a free standing thick polymer film. The proposed formulae are then used to simulate the diffuse reflectance and diffuse transmittance. Analysis results indicate that internal reflectance is not a constant and varies with film thickness and absorption property. Internal reflectance of the front surface (irradiated surface) surpasses that of the back surface. In addition, all the internal reflectances decrease with the film thickness and the absorption property. In light of the measured thickness and experimentally determined diffuse transmittance of a polymer film, the extinction coefficient to diffuse IR irradiation can be obtained by interpolating in the graphs provided in this study.