Transient Thermal-History Measurement During Photopolymerisation

Photopolymerisation couples a light-driven reaction to heat generation, heat transport and temperature-dependent kinetics. A measured temperature trace is therefore neither a direct measure of conversion nor a pure record of reaction enthalpy. It is the result of local heat generation, conduction into tooling and previously cured material, convection in liquid resin, radiation, changing material properties, source heating, sensor response and the location at which temperature is observed.

This review defines a measurement architecture for transient thermal history during photopolymerisation. Photo-differential scanning calorimetry, embedded sensors, infrared thermography and inverse heat-conduction models are compared by their measurands and perturbations. The review separates directly observed temperature and heat flow from inferred volumetric heat generation and inferred cure state. It examines spatial and temporal resolution, emissivity, sensor lag, contact resistance, boundary conditions and the non-uniqueness of inverse attribution. A validation hierarchy links calibrated temperature measurement to independent spectroscopy or calorimetry without assuming a universal heat of reaction. The result is a framework for reporting where and when temperature was measured, what model converted it into chemical information and which conclusions remain conditional. No universal cure-temperature or safety limit is proposed.