In-Situ Monitoring of Solidification Process of PVA Solution by Fiber Optic Sensor Technique

In this research, we monitored the solidification process of PVA solution using a fiber optic refractive index sensor. During the monitoring process in this paper, two Fabry-Pérot cavities were used to monitor the temperature and the refractive index of the PVA sample. The advantage of this method is that the related refractive index change is obvious, and the status of materials can be directly observed during the testing process. Furthermore, this method can be more cost-effective compared with its heat flow-based counterpart. Differential scanning calorimetry (DSC) tests were performed with the same material and the heating rate. Compared with the result given by DSC, the detected temperature range when the phase of PVA solution changes is much narrower. The method suggested in this paper is potentially useful to monitor the solidification process of transparent materials in an easier and cost-effective way.