Quantitative Laser Beam Deflection Study Interdiffusion in the Water-Sugar System of Liquid-Liquid

Purely concentration-gradient driven liquid-liquid interface laser beam deflection detection was studied theoretically and used experimentally to monitor the kinetics of diffusion between water and sugar as a simple model system. The combination of data from both sides of the interface was used to determine the initial position of the interface plane. The developed one-dimensional model of the dependence of the laser beam deflection on the diffusion parameters was found to be in good agreement with the experimental data, especially at early interdiffusion times. The model was thus able to yield the values for the diffusion coefficient DS of sugar in water, and for the refractive index gradient an/3C