function tg = tg_function(Tg_0,c,rho_L)


R = 8.31; % J/(mol K) gas constant

z = 2; % - lattice coordnation number

M_p = 100.12*10^-3; % kg/mol molecular weight polymer repeat unit

M_d = 44.01*10^-3; % kg/mol molecular weight gas molecule

delta_Cp = 355; % J/(kg K) 



c_weight = c*M_d/(rho_L);

theta = M_p*c_weight/(z*M_d*(1-c_weight));

beta = z*R/(M_p*delta_Cp);

tg = Tg_0*exp(beta*((1-theta)*log(1-theta)+theta*log(theta)));
 
 end