Final answer:
Glass undergoes long timescale stress relief due to its viscoelastic properties.
Step-by-step explanation:
Glass undergoes long timescale stress relief due to its viscoelastic properties. When glass is subjected to stress, such as during the manufacturing process or due to temperature changes, it takes time for the internal structure of the glass to adjust and release the stress. This process can take hours to days, depending on the specific composition and conditions of the glass.