TURBIDITY SPECTRA OF TUNGSTIC ACID IN GELATION PROCESS

Time-resolved transmitted light spectra (lambda = 400 approximately 800 nm) through gelling tungstic acid have been observed. As the gelation proceeds, intensity of the transmitted light decreases, remarkably in the short-wavelength region. It is found that ln tau (tau; turbidity) shows approximately linear dependence on ln lambda, and that the slope varies as proceeding the gelation. These results can be explained by increase in the internal interference of the scattered lights from growing cluster.