The first buffer, built around U701A provides a low-impedance source for the glide pot which in turn with C701 provides an RC time delay on the control voltage. The resultant voltage on the C701 is then buffered by U701B which also provides a low-impedance source for the following modules.
This general configuration provides for an exponential glide. By inserting R701 in series with P701 and C701, a more linear charge/discharge curve is achieved.