  The form of the low-temperature interactions between defects in neutral
glasses is reconsidered. We analyse the case where the defects can be modelled
either as simple 2-level tunneling systems, or tunneling rotational impurities.
The coupling to strain fields is determined up to 2nd order in the displacement
field. It is shown that the linear coupling generates not only the usual
$1/r^3$ Ising-like interaction between the rotational tunneling defect modes,
which cause them to freeze around a temperature $T_G$, but also a random field
term. At lower temperatures the inversion symmetric tunneling modes are still
active - however the coupling of these to the frozen rotational modes, now via
the 2nd-order coupling to phonons, generates another random field term acting
on the inversion symmetric modes (as well as shorter-range $1/r^5$ interactions
between them). Detailed expressions for all these couplings are given.
