getting ‘stuck’ in their nearest-neighbor cages. This can be compared with previous work [@HSglass; @HSnonergodicity]. Note that in doing so, it is important to compare samples with the same density [*relative to random close packing*]{}: i.e. the same $(\phi_{\rm
rcp}-\phi)/\phi_{\rm rcp}$, since $\phi_{\rm rcp}$ differs according to the polydispersity of the colloids [@polyrcp].

With a small amount of polymer added to the hard-sphere glass, sample B shows the same qualitative dynamics. Quantitatively, however, the height of the plateau is lower, $f(q,\infty) = 0.62$. This indicates that particles in B are not as restricted as in A, i.e. the cage is loosened by the attractive interaction, but still remains closed in our time window.

The DSF of sample C decayed completely in (a ‘scaled time’ of) about 1000 seconds, as did those for the other crystallizing samples D and E. It is interesting to note that the DSFs of these three samples slow down upon increasing polymer concentration but all reach zero at about the same scaled time. The DSF of sample C shows the remnant of a plateau at a scaled time of $ \approx$ 10 s. The DSFs for samples D and E exhibit a very stretched [*single*]{} decay, 