Measurement of dimensional changes in thin polymer films - Flexible magnetic disks consist of a thin polymer substrate with a magnetic coating. During its lifetime, a disk will experience in-plane deformation which must be accurately measured for optimum performance

Instrumentation is described to measure dimensional changes of polymer films in strip and disk form. Experimental results are presented for the time-dependent radial deformation of a rotating disk due to stress relaxation, creep and environmental changes such as temperature and humidity. In addition, measurement of longitudinal extension and lateral contraction of a narrow strip under uniaxial tension is discussed. © 1978 Society for Experimental Mechanics, Inc.