Dynamic Laser Speckle Imaging as a Nondestructive Method for Tracking the Dynamics in Slow Curing Epoxy Resin

Dynamic laser speckle imaging (DLSI) is an emerging nondestructive optical method used for the characterization of turbid materials. The microscopic dynamics of the turbid materials can be quantified using this imaging technique with high spatio temporal resolution. In recent decades, epoxy resins became indispensable for industries due to its fascinating mechanical properties, high chemical resistance, etc. The physical, mechanical and electrical characteristics of epoxy resins depend on the curing process. However, the techniques for monitoring the microscopic dynamics of the curing process are in-sufficient. Hence this work reports the application of dynamic laser speckle imaging to monitor the curing stages of Araldite, a 2 part epoxy resin. The computational methods incorporated with the technique include cross-correlation, inertia moment, Fujii method, etc. Conventional characterization techniques such as Differential Scanning Calorimetry and Fourier Transform Infrared Spectroscopy were also employed to confirm the results. The experimental results were also confirmed using the theoretical analysis.