Optical Study on the Resultant Movement of Many Walls in Rochelle Salt

A new optical device to study the resultant movement of many walls in rochelle salt was constructed. It was found that the rotating angle of the optical plane is nearly in proportion to the spontaneous polarization. Some characteristics of the resultant wall motion were studied from the information of the rotating angle. From these experimental results we are inclined to conclude that the fatigue effect will be caused by either the displacement of dislocations or neutral vacancies.