Diffusion in confinement as a microscopic relaxation mechanism in glass-forming liquids

► Glass-forming and non glass-forming liquids are studied using quasielastic scattering. ► Glass-formers exhibit two separate relaxation components, non glass-former only one. ► The faster of the two components corresponds to the β-relaxation process. ► The β-relaxation can be described as a diffusion process in confined space (cage).