The characteristic properties of relaxation processes for 55Bi 2 O 3 ⋅ 45B 2 O 3 glass were described. The pattern of changes of the vitrification temperature (T g ) is found to be quasi periodic; the value of the endothermic effect near T g () and the difference between the softening point and the vitrification tem perature (T m -T g ) were determined. The temperature time parameters of the transition from quasi periodic to the continuous change of the properties were determined and an explanation of such behavior of the system was offered.Keywords: 55Bi 2 O 3 ⋅ 45B 2 O 3 glass, thermal behaviour, T g , relaxation