Internal structures such as crystallinity (lamellar and spherulitic structures) can be determined by using polarized light microscopy, TEM, and in some cases SEM depending on how the sample is fractured and the type of sample being analyzed.

* EDX is Energy Dispersive X Ray, LOM is Light Optical Microscopy, OC is Optical Comparator, SEM is Scanning Electron Microscopy, TEM is Transmission Electron Microscopy