A toy MCT model for multiple glass transitions: Double swallow tail singularity

•A simple toy model is proposed for description of glass–glass transitions.•The static structure factor of the model has the form of a sum of delta-functions.•The phase diagram contains A4A4 bifurcation singularities and A3A3 end points.•The results can be applied for the qualitative description of quasibinary systems.

We propose a toy model to describe in the frame of Mode Coupling Theory multiple glass transitions. The model is based on the postulated simple form for static structure factor as a sum of two delta-functions. This form makes it possible to solve the MCT equations in almost analytical way. The phase diagram is governed by two swallow tails resulting from two A4A4 singularities and includes liquid–glass transition and multiple glasses. The diagram has much in common with those of binary and quasibinary systems.