in the first day or two, after which they did not evolve within the time window of the measurements. Attractive glasses, on the other hand, showed different dynamics with age for up to 10 days. Aging is complicated enough to be the subject of a separate study and was not investigated systematically in this work. To eliminate as much as possible aging effects on dynamical results within practical limits of waiting time, we present DSFs of glassy samples with age between 1 and 4 days. The dynamics of crystallizing samples (C–E) were measured while they were in the metastable state well before the appearance of crystallization. Below we first show results of different samples at the same $q$, then at different $q$ for the same sample.

### Constant scattering vectors, variable compositions

The DSFs of samples A–H at $qR=1.50$, Fig. \[fig:up0.6q23\], clearly evolve non-monotonically with increasing polymer concentration and show re-entrant behavior. Briefly, samples A and B are non-ergodic within our time window, while samples C–E are ergodic (their DSFs decay completely to zero), and samples F–G become non-ergodic again.

In detail, the DSF of sample A, a pure hard-sphere glass, shows a plateau at $f_A(q,\infty)\approx 0.7$, corresponding to particles 