Which process is used for styling hair by applying heat in combination with a chemical solution?

The process used for styling hair by applying heat in combination with a chemical solution is known as thermal styling. This technique involves using heated tools, such as curling irons or flat irons, to alter the hair's structure temporarily while often working in conjunction with products that provide hold or additional texture.

Thermal styling can enhance hair's appearance by creating curls, waves, or straightening it, depending on the desired outcome. The application of heat helps in reshaping the hair, which is particularly effective when combined with styling products formulated to protect the hair from damage and enhance styling longevity.

Other options refer to different processes: permanent waving specifically involves using chemicals and heat to create lasting curls, relaxing is a process designed to chemically alter the structure of curly hair to make it straight, and color treating focuses on changing the color of the hair using dye or bleach, rather than styling. Each of these methods serves a unique purpose in haircare and styling.