Determining method for glass board fracture toughness

The invention relates to the field of photoelectric glass production and discloses a determining method for glass board fracture toughness. The method comprises the steps of determining the thickness W and width B of a glass board sample; joint cutting treatment is performed on the long side face of the glass board sample in the width direction, and the depth C of a cut joint is determined; a glass board is placed in the mode that the cut joint is placed downwards so as to perform three-point bending determination, a fracture load P of the glass board sample is determined, and a fracture toughness value KIC of the glass board sample is calculated on the basis of the equation that KIC=P*S*f(C/W)/(B*W3/2). According to the determining method, the fracture extension characteristics of an actual glass board can be effectively stimulated, and the determined fracture toughness data provides the reliable basis for accurately estimating the performance of the glass board.