A kit having a supporting device for maintaining a transparent article having a longitudinal axis A, a proximal end and a distal end. The supporting device including a proximal holder including a port intended to receive the proximal end of the article, and a distal holder including a receiving part intended to receive the distal end of the article, the port and the receiving part being aligned on the same longitudinal axis B. The supporting device further having a compressor for putting the article under longitudinal compression directed towards a center of the article, when the article is mounted on the supporting device with its longitudinal axis A aligned on the longitudinal axis B, and a polarimeter. The invention also pertains to a method for measuring the stress inside an article made of transparent material.