Volume 26, Issue 2 (April 1981)
Fluorescence Spectrometry in the Identification and Discrimination of Float and Other Surfaces on Window Glasses
Fluorescence spectra have been obtained with conventional spectrometers from glass.surfaces varying in area down to 0.05 mm2 on fragments as small as 18 μg in mass. In such fragments several fluorescence features can be identified, including the tin fluorescence typical of float surfaces. Float surface fragments may therefore be unambiguously differentiated from other surface fragments by their fluorescence excitation spectra. Thus, in many cases the forensic scientist may now show that the type of glass surface facing the person alleged to have broken it is or is not of the same type as any incriminating fragments. Within the two classes of glass (float and nonfloat) appreciable variation occurs in relative fluorescence intensities. For float glasses there is negligible correlation between the tin fluorescence intensity and any refractive index feature, including the recently reported surface refractive index that is also characteristic of glass of this type.