  The opportunity to build quantum technologies operating with elementary
quantum systems with more than two levels is now increasingly being examined,
not least because of the availability of such systems in the laboratory. It is
therefore essential to understand how these single systems initially in highly
non-classical states decohere on different time scales due to their coupling
with the environment. In this work, we consider the depolarization, both
isotropic and anisotropic, of a quantum spin of arbitrary spin quantum number
$j$ and focus on the study of the most superdecoherent states. We approach this
problem from the perspective of the collective dynamics of a system of $N=2j$
constituent spin-$1/2$, initially in a symmetric state, undergoing collective
depolarization. This allows us to use the powerful language of quantum
information theory to analyze the fading of quantum properties of spin states
caused by depolarization. In this framework, we establish a precise link
between superdecoherence and entanglement. We present extensive numerical
results on the scaling of the entanglement survival time with the Hilbert space
dimension for collective depolarization. We also highlight the specific role
played by anticoherent spin states and show how their Markovian isotropic
depolarization alone can lead to the generation of bound entangled states.
