Glasses of composition M2O.2SiO2 (M= Li, Na, K, Rb and Cs) were obtained by means of molecular dynamics simulation.The structures of these glasses were analyzed with help of Q-speciesdistribution. The influence of alkali oxide on a decay of Q-species is monitoredaccording to the equation 2Qn « Qn-1+ Qn+1. Equilibrium constant of this equation is defined by therelation kn = [Qn-1][Qn+1]/[Qn]2.It was found that k3 is decreasing in sequence Li > Na > K sothat the decay of Q3 is preferred for smaller alkali ions. Systemswith higher k3 tend to create the silicate-rich regions (abundant inQ4) and alkali-rich regions where alkali ions are spread amongchain-like structures formed by Q2 units. For larger alkali size, k3increases as K < Rb < Cs. This phenomenon is probably caused by slowerrelaxation of simulated glasses with a large alkali ion.
