Glows cannot be seen through transparent objects, nor in reflections. The glow you specify here does not act as a light; other parts of the scene will not be lit by the glow, nor will any shadows be cast. Glows are restricted to a maximum image resolution of 4,000 x 4,000 pixels.
Inner Strength specifies the intensity of the glow over the surface; Outer Strength is the intensity of the glow at the edges.
The Radius determines how far the glow (either the inner or the outer) extends from the surface. This value is rendered relative to the distance of the object from the camera. The further away the object is, the smaller the glow, and vice versa.
If a random percentage is defined, the intensity of the glow in each animation frame is increased and decreased in a random pattern, as follows:
Frequency specifies how often the glow radius changes. The amplitude of the change is given by the Random value.
If Use Surface Color is enabled, the glow is calculated on the basis of the surface color rather than the color specified here.
If the option is disabled, the object and glow colors are mixed. For example, green objects will appear yellowish under a red glow.