SUPPRESSION OF INTERFERENCE-FRINGES IN THE INFRARED-SPECTRA OF THIN POLYMER-FILMS

Infrared transmission spectra of polymer films, such as films of poly(styrene), are characteristically complicated by the presence of interference fringes. This simple technique of combining various rays to for obtain fringe-free infrared spectra offers many advantages over the other methods in use. Most importantly, the technique yields true, reproducible transmission spectra which may be used in quantitative analysis. The technique is nondestructive; hence the samples can be used repeatedly. No prior sample preparation is necessary. The technique is simple to use, and if they have not been purchased, the optics are readily constructed.