During the stress relaxation: polymers remain under a fixed strain. Using the definition of the Relaxation Time constant; "a material property that defines the time needed for the instantaneous stress to decrease to 37% the initial stress", explain why the change in the load is greater at the beginning of the two minutes? The glass transition temperature (Tg) is the temperature for which a material goes from a viscous or rubbery state to a more solid-like state. Polylactic acid (PLA) is a polymer commonly used in 3D printing applications. It has a relatively low Tg of 60-65 C. Knowing this, would using PLA for applications such as a flexible spatula (useful when frying eggs and such) be a good idea? Why? If not, what property should be desired when choosing another polymer? How does the microstructure affect the materials maximum allowable strain? Are polymers elastic, viscoelastic or viscous? What does this mean?