How do short-wave infrared lamps expedite the curing process of paint?

Short-wave infrared lamps expedite the curing process of paint primarily by exciting the molecules of the substrate. When these lamps are used, they emit infrared radiation that penetrates the paint and the underlying material, causing the molecules to vibrate and increase their energy level. This heightened molecular activity accelerates the chemical reactions involved in the curing process, allowing the paint to set and harden more quickly.

The other choices, while they might seem plausible, do not accurately describe the fundamental mechanism by which short-wave infrared lamps facilitate curing. Reducing temperature would actually slow down curing instead of promoting it. Rapid evaporation of solvents can occur, but it’s the molecular excitation that primarily drives the curing. Applying pressure is not a relevant factor in the curing process related to infrared lamps; it's more applicable to other methods in paint application or adhesion processes. Thus, the excitation of molecules stands out as the key reason for the expedited curing process.