The combination of infrared spectroscopy and chemometric data analysis has been shown to provide a valuable method for rapid, nondestructive, at-line characterization of film properties for a variety of thin films. We demonstrate the precise determination of As content and film thickness for arsenosilicate glass thin films. Calibrations based on the infrared data yielded standard errors of prediction of 0.10 wt. % and 10 angstrom for the arsenic content and film thickness, respectively. Further, it is demonstrated that profiling the film properties across the wafer surface can increase the accuracy of the determinations by improving the correspondence of the infrared and reference property measurements. This profiling also provides rapid information about spatial variations of film properties.