  We study the process of formation of quark phases in protoneutron stars.
After calculating the phase transition between nucleonic matter and the 2SC
phase at fixed entropy and lepton fraction, we show that an unpairing
transition between the 2SC phase and the normal quark phase occurs for low
lepton fractions. We then calculate the process of diffusion of neutrinos in
protoneutron stars and show that for intermediate values of the mass of the
star, the deleptonization triggers the phase transition between the two quark
phases after a temporal delay of a few seconds. In less massive stars instead
only the normal quark phase is formed at the end of the deleptonization stage.
We also discuss the possible astrophysical implications of our scenario.
