I have taken data for the transmission vs. wavelength for several types of glasses in the IR. I want to convert this to absorbance so that I can generalize transmission to different thickness glasses. I found an equation online that stated A = 2-Log(T%) (where Log is base 10). But I do not see how this considers thickness. Does anyone know how I can translate knowing the transmission % for a specific thickness glass to knowing the absorbance/transmission to thicker glasses?