Hello dear in waterborne coatings can occur to process:

1) Physic process (Firt process)

In this process happen a solvent evaporation, in your case of the water, this process is depending on conditions, especially humidity percentage.

2) Chemical process (Second process)

In this process occur crosslinking of the polymers (Curing) due to the formation of covalent bonds between the chain of the polymers, ussually it is performed by using a catalyzer, this process occur in the Polyurethane, alkyd resins, epoxy resins, etc.

In this process is formed the film of the polymer on the surface of a substrate.

In your case occur the physics and chemical processes