Syntax error, need help with this 'string'

Question

I have this piece of code here below:

$fq.=" + (fritidsboende_uth_from:[$fritids_uth_from TO *] 
AND fritidsboende_uth_to:[* TO $fritids_uth_to]) 
OR (fritidsboende_uth_from:'1972-01-01T01:01:00Z' 
AND fritidsboende_uth_to:'2019-01-01T01:01:00Z')";

I have noticed my app doesn't get anything behind the colon, in this part of the code:

  OR (fritidsboende_uth_from:'1972-01-01T01:01:00Z' // Notice the colon in the date string

I get this error msg: Unrecognized date string: '1972-01-01T01'. Nothing from behind the colon is there though.

How should I 'escape' it so that the colon is properly recognized?

Its PHP...

Thanks

UPDATE:

I have this querystring, so maybe the colon is lost in this translation...hmm...

+%28fritidsboende_uth_from%3A%5B2010-04-09T01%3A01%3A00Z+TO+%2A%5D+AND+fritidsboende_uth_to%3A%5B%2A+TO+2010-04-10T01%3A01%3A00Z%5D%29+OR+%28fritidsboende_uth_from%3A1972-01-01T01%3A01%3A00Z+AND+fritidsboende_uth_to%3A2019-01-01T01%3A

Answer 1

EDIT based on SOLR comment by OP

try adding braces and complete the ranges, like:

$fq.=" + (fritidsboende_uth_from:[$fritids_uth_from TO *] 
AND fritidsboende_uth_to:[* TO $fritids_uth_to]) 
OR (fritidsboende_uth_from:[1972-01-01T01:01:00Z TO *] 
AND fritidsboende_uth_to:[* TO 2019-01-01T01:01:00Z])";

see: http://stackoverflow.com/questions/796753/solr-fetching-date-ranges