This can either be played as a natural harmonic glissando or a false harmonic glissando both resulting in different effects.
Natural harmonic Glissando
Using this technique I found that a firm even bow stroke was best so that the harmonics can catch, with a fast glissando it works best on the lower strings as the higher harmonics don’t have time to catch. A slow glissando on the G would optimise all the harmonic series and would bring out all the minute sounds between the nodes. I particularly like the effect when the finger sliding from the end of the fingerboard to the bow as the effect is a light fluttering sound.
False Harmonic Glissando
There are two ways of producing a false harmonic glissando, the first being to perform a false harmonic with the first finger stopped slide the fourth finger, lightly touching the string, towards the stopped finger. The closer the fourth finger gets to the first finger the higher the pitch of the harmonic.
The second way to perform a false harmonic glissando is to perform it with a fixed hand. This means that when you perform the harmonic you slide the whole hand. As a performer you would have to remember that the higher up the fingerboard you went with the glissando you would have to move your fingers slightly closer together to keep the tone correct. Legeti uses this technique in his piece Ramifications.