To get this look, first apply the Text filter, ensuring that the text is INVERTED by tapping the center style icon in the Text filter, then tapping the Invert icon. Once applied, open the edit stack by tapping the number icon in the upper right corner. Tap on the Text filter twice to open the option menu, then tap on the Brush icon. Set the brush opacity to 75 and brush on the full text. Then, set the opacity to 100 and brush in the middle of the letters so that the glow appears brighter in the center and fades out. Finally, set the brush opacity to zero and erase around the words, leaving only enough of the color to show the outline of the letters.
Don't forget that zooming in and out of the brush will change the brush size, so zoom in for a finer tipped brush if needed.