Polarized Optical Microscopy (POM) is a technique used to quantitatively and qualitatively characterize birefringent samples. Image contrast arises from the optically anisotropic samples interacting with plane polarized light to produce two individual, perpendicular wave components. POM is commonly used to study crystalline morphology in plastics and composites, as well as to visualize fundamental polymer orientations and crystallization phenomena. It is well-known that manufacturing, processing, and material properties of plastics are dependent on crystalline characteristics, such as kinetic rate, shape, size, type, and conformation in composites. Manipulation of these crystalline characteristics is common practice in order to improve the processing conditions and material properties which directly impact their industrial applicability. Polylactic acid (PLA), an industrially compostable biopolyester, is an example of a polymer whose crystalline characteristics have been well studied for this purpose. This talk details the theory behind POM and its use in studying the crystalline morphology and manipulations of PLA in order to determine its potential as an environmentally friendly substitute for petroleum-based non-biodegradable polymers.