Transmission photoelasticity was used to obtain an experimental solution for stress intensity factors, KI, due to thermal loads in photoelastic models. In a photoelastic plate, a slot to simulate a crack was introduced. Also, a tube to circulate a coolant was fixed in one of the edges of the plate. The photoelastic model was putted on a photoelastic oven and kept at 60 ??C. Then, methyl alcohol at -15 ??C circulated through the cooling tube. The thermal shock in the plate caused stress on it and, as a consequence, transient photoelastic fringe patterns appeared and were captured by an image acquisition system. For each captured photoelastic fringe pattern, the stress intensity factor KI was determined using a dedicated software, specially developed to do it, based on the Dally overdeterministic method. This results are compared with numerical analyses. Based on the obtained results, some conclusions and recommendations on the experimental techniques used were addressed. The paper present a alternative experimental methodology for evaluation of stress intensity factors due thermal loads. The construction of the models can be very simple, the used equipments can be of easy acquisition or manufacture. In this aspect, it should be noticed that in spite of the polariscope used in this work is quite sophisticated, it is necessary a rudimentary polariscope to conduct these type of experiments, just constituted of a light source and plane polarizers plates easily found.