The participial phrase from the sentence is "removing his glasses".
Explanation:
A participle begins with a present or past participle. If the participle is present it ends in -ing, and if it is a regular verb its past participle form ends in -ed. A participle phrase will often include objects and/or modifiers. In this case, the participle <em>removing</em> takes the NP "his glasses" as its direct object.
