High-speed photo-elastic color photography was introduced to a study of dynamic crack propagation in zone-tempered glass using recent photo-processing technologies. The study had a special focus on the value of stress σ_CR generated at the propagating crack front. It was recognized that the crack connection phenomenon could be explained using the stress σ_CR. The values of stress σ_CR were estimated at about 5 MPa in zone 1 and 3–4 MPa in zone 2 utilizing the color change of the stress field when propagating at terminal velocity. A slant-propagating crack was observed, which could be explained by a generation mechanism involving the stress σ_CR and the stress release, and propagation in the same way as other general crack propagation based on the maximum normal stress criterion.