The problem of reflection and refraction phenomenon due to plane waves incident obliquely at the loosely bonded interface between an elastic solid half-space and the microstretch thermoelastic diffusion solid half-space is discussed. It is assumed that the interface behaves like a dislocation, which preserves the continuity of traction while allowing a finite amount of slip. The amplitude ratios of various reflected and transmitted waves to that of incident wave are obtained. These amplitude ratios are further used to find the expressions of energy ratios of various reflected and refracted waves to that of incident wave. Numerical results have been obtained for a particular model to study the variation of energy ratios with respect to angle of incidence. The effect of relaxation times and loosely bonding parameters are shown with energy ratios for a specific model. The law of conservation of energy at the loosely boundary interface is verified. Some special cases of interest have been deduced from the present investigation.