RAMAN IMAGING OF HETEROGENEOUS POLYMERS - A COMPARISON OF GLOBAL VERSUS POINT ILLUMINATION

Two alternative methods of Raman imaging, via global (wide-field) illu mination and via point illumination in combination with confocal light collection, have been applied to the study of heterogeneous polymer s ystems. From the results obtained it becomes apparent that the fluores cence inherent to most polymer systems severely limits the use of glob al illumination. Furthermore, the lack in depth resolution in Raman im aging by global illumination ruled out this method for the study of bu lk polymer samples. Also as a consequence of the absence of depth reso lution, the global illumination technique appeared more vulnerable to artifacts arising from scattering effects due to the sample geometry a nd fluorescence. Hence, for a general application of Raman imaging to the study of polymer samples, Raman imaging by point illumination in c onjunction with confocal light collection is the method of choice.