The thermal and mechanical properties of polymeric materials are fundamentally connected with the topological details at the molecular level. While ideas such as entanglement, chain mobility, and free volume can be presented as models or equations in the textbooks, they are often challenging to quantify and visualize by experiments. By exploring fluorescent molecular rotors that changes their emission properties in response to the changing environments, we seek to develop new probes to deepen our understanding of polymer physics at the molecular level and their connection to the macroscopic properties of a material.