The electro-magnetically spinning (EMS) viscometer we recently developed enables non-contact viscosity measurement. The measurement sample is confined in an isolated sample cell, and the viscosity, which is one of the most important mechanical parameters to determine ultrasonic propagation in fluids, is easily obtained in a few minutes for lower-viscosity liquids. In this paper, we report an improved system for the measurement of highly viscous liquids: laser light is incident on a probe metal sphere, and the speckle pattern generated by the scattered light is observed using detectors aligned along a circle around the center of the speckle rotation. We successfully measured a viscosity of 103 Pa·s within only 0.1 s, demonstrating the system’s ability to measure rapid changes of viscosity, for example, in a material undergoing the glass transition.
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