  After being produced as electron neutrinos ($\nu_e$), solar neutrinos
partially change their flavor to $\nu_{\mu}$ and $\nu_{\tau}$ en route to
Earth. Although the flavor ratio of the $\nu_e$ flux to the total flux has been
well measured, the $\nu_{\mu}:\nu_{\tau}$ composition has not yet been
experimentally probed. In this work we investigate the potential of the
next-generation experiments for measuring the $\nu_{\mu}:\nu_{\tau}$ flavor
ratio by utilizing flavor-dependent radiative corrections in the cross sections
for $\nu_{\mu}$ and $\nu_{\tau}$ scattering. Since the transition probabilities
of $\nu_e$ to $\nu_\mu$ and $\nu_\tau$ depend on the leptonic CP phase, we also
investigate the sensitivity to the CP phase and show that a statistical
significance of $\sim1 \sigma$ could be reached through precision measurements
of solar neutrino spectra.
