Abstract: The associating state of dyes in solution plays an important role in dyeing. The effects of ultrasound on dye associating state was studied in terms of the determination of conductivity and absorption spectrum of the dye liquor in this paper. The results showed that the maximum absorption wavelength(λmax) of the dye solution exhibited a blue shift with the increase in the concentration of Weak Acidity Oprah 's Red B solution and, its aggregation concentration was determined as 1×10-5 mol/L. As the temperature increases, the increase of the conductivity of the dye solution undergoing ultrasonication was higher than that of the dye solution without standing ultrasonication, when the dye solution was above the aggregation concentration. At 50℃, the electrical conductivity of the dye solution gradually increased with the ultrasonication time, and a red shift of the λmax occurred, and with a decrease in the absorbance of spectrum shoulder peak.

Key words: ultrasonic wave, dye, association, electric conductivity, absorption spectrum